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743 lines
23 KiB
743 lines
23 KiB
//---------------------------------------------------------------------------- |
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// Anti-Grain Geometry - Version 2.3 |
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com) |
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// |
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// Permission to copy, use, modify, sell and distribute this software |
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// is granted provided this copyright notice appears in all copies. |
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// This software is provided "as is" without express or implied |
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// warranty, and with no claim as to its suitability for any purpose. |
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// |
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// The author gratefully acknowleges the support of David Turner, |
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// Robert Wilhelm, and Werner Lemberg - the authors of the FreeType |
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// libray - in producing this work. See http://www.freetype.org for details. |
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// |
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//---------------------------------------------------------------------------- |
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// Contact: mcseem@antigrain.com |
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// mcseemagg@yahoo.com |
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// http://www.antigrain.com |
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//---------------------------------------------------------------------------- |
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// |
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// Class rasterizer_scanline_aa |
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// |
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// |
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//---------------------------------------------------------------------------- |
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#ifndef AGG_RASTERIZER_SCANLINE_AA_INCLUDED |
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#define AGG_RASTERIZER_SCANLINE_AA_INCLUDED |
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#include <string.h> |
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#include <math.h> |
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#include "agg_basics.h" |
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#include "agg_math.h" |
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#include "agg_gamma_functions.h" |
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#include "agg_clip_liang_barsky.h" |
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#include "agg_render_scanlines.h" |
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|
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namespace agg |
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{ |
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|
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//------------------------------------------------------------------------ |
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// These constants determine the subpixel accuracy, to be more precise, |
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// the number of bits of the fractional part of the coordinates. |
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// The possible coordinate capacity in bits can be calculated by formula: |
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// sizeof(int) * 8 - poly_base_shift * 2, i.e, for 32-bit integers and |
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// 8-bits fractional part the capacity is 16 bits or [-32768...32767]. |
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enum |
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{ |
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poly_base_shift = 8, //----poly_base_shift |
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poly_base_size = 1 << poly_base_shift, //----poly_base_size |
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poly_base_mask = poly_base_size - 1 //----poly_base_mask |
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}; |
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|
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//--------------------------------------------------------------poly_coord |
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inline int poly_coord(double c) |
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{ |
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return int(c * poly_base_size); |
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} |
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|
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//-----------------------------------------------------------------cell_aa |
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// A pixel cell. There're no constructors defined and it was done |
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// intentionally in order to avoid extra overhead when allocating an |
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// array of cells. |
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struct cell_aa |
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{ |
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int16 x; |
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int16 y; |
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int packed_coord; |
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int cover; |
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int area; |
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|
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void set(int x, int y, int c, int a); |
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void set_coord(int x, int y); |
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void set_cover(int c, int a); |
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void add_cover(int c, int a); |
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}; |
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|
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//--------------------------------------------------------------outline_aa |
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// An internal class that implements the main rasterization algorithm. |
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// Used in the rasterizer. Should not be used direcly. |
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class outline_aa |
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{ |
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enum |
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{ |
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cell_block_shift = 12, |
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cell_block_size = 1 << cell_block_shift, |
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cell_block_mask = cell_block_size - 1, |
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cell_block_pool = 256, |
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cell_block_limit = 1024 |
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}; |
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public: |
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~outline_aa(); |
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outline_aa(); |
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void reset(); |
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void move_to(int x, int y); |
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void line_to(int x, int y); |
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int min_x() const { return m_min_x; } |
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int min_y() const { return m_min_y; } |
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int max_x() const { return m_max_x; } |
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int max_y() const { return m_max_y; } |
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const cell_aa* const* cells(); |
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unsigned num_cells() { cells(); return m_num_cells; } |
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bool sorted() const { return m_sorted; } |
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private: |
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outline_aa(const outline_aa&); |
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const outline_aa& operator = (const outline_aa&); |
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void set_cur_cell(int x, int y); |
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void add_cur_cell(); |
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void sort_cells(); |
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void render_hline(int ey, int x1, int y1, int x2, int y2); |
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void render_line(int x1, int y1, int x2, int y2); |
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void allocate_block(); |
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|
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static void qsort_cells(cell_aa** start, unsigned num); |
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private: |
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unsigned m_num_blocks; |
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unsigned m_max_blocks; |
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unsigned m_cur_block; |
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unsigned m_num_cells; |
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cell_aa** m_cells; |
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cell_aa* m_cur_cell_ptr; |
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cell_aa** m_sorted_cells; |
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unsigned m_sorted_size; |
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cell_aa m_cur_cell; |
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int m_cur_x; |
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int m_cur_y; |
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int m_min_x; |
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int m_min_y; |
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int m_max_x; |
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int m_max_y; |
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bool m_sorted; |
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}; |
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//----------------------------------------------------------filling_rule_e |
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enum filling_rule_e |
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{ |
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fill_non_zero, |
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fill_even_odd |
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}; |
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//==================================================rasterizer_scanline_aa |
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// Polygon rasterizer that is used to render filled polygons with |
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// high-quality Anti-Aliasing. Internally, by default, the class uses |
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// integer coordinates in format 24.8, i.e. 24 bits for integer part |
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// and 8 bits for fractional - see poly_base_shift. This class can be |
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// used in the following way: |
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// |
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// 1. filling_rule(filling_rule_e ft) - optional. |
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// |
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// 2. gamma() - optional. |
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// |
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// 3. reset() |
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// |
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// 4. move_to(x, y) / line_to(x, y) - make the polygon. One can create |
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// more than one contour, but each contour must consist of at least 3 |
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// vertices, i.e. move_to(x1, y1); line_to(x2, y2); line_to(x3, y3); |
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// is the absolute minimum of vertices that define a triangle. |
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// The algorithm does not check either the number of vertices nor |
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// coincidence of their coordinates, but in the worst case it just |
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// won't draw anything. |
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// The orger of the vertices (clockwise or counterclockwise) |
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// is important when using the non-zero filling rule (fill_non_zero). |
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// In this case the vertex order of all the contours must be the same |
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// if you want your intersecting polygons to be without "holes". |
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// You actually can use different vertices order. If the contours do not |
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// intersect each other the order is not important anyway. If they do, |
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// contours with the same vertex order will be rendered without "holes" |
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// while the intersecting contours with different orders will have "holes". |
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// |
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// filling_rule() and gamma() can be called anytime before "sweeping". |
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//------------------------------------------------------------------------ |
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template<unsigned XScale=1, unsigned AA_Shift=8> class rasterizer_scanline_aa |
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{ |
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enum status |
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{ |
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status_initial, |
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status_line_to, |
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status_closed |
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}; |
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struct iterator |
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{ |
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const cell_aa* const* cells; |
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int cover; |
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int last_y; |
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}; |
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public: |
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enum |
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{ |
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aa_shift = AA_Shift, |
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aa_num = 1 << aa_shift, |
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aa_mask = aa_num - 1, |
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aa_2num = aa_num * 2, |
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aa_2mask = aa_2num - 1 |
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}; |
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//-------------------------------------------------------------------- |
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rasterizer_scanline_aa() : |
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m_filling_rule(fill_non_zero), |
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m_clipped_start_x(0), |
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m_clipped_start_y(0), |
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m_start_x(0), |
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m_start_y(0), |
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m_prev_x(0), |
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m_prev_y(0), |
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m_prev_flags(0), |
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m_status(status_initial), |
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m_clipping(false) |
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{ |
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int i; |
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for(i = 0; i < aa_num; i++) m_gamma[i] = i; |
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} |
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//-------------------------------------------------------------------- |
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template<class GammaF> |
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rasterizer_scanline_aa(const GammaF& gamma_function) : |
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m_filling_rule(fill_non_zero), |
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m_clipped_start_x(0), |
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m_clipped_start_y(0), |
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m_start_x(0), |
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m_start_y(0), |
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m_prev_x(0), |
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m_prev_y(0), |
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m_prev_flags(0), |
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m_status(status_initial), |
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m_clipping(false) |
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{ |
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gamma(gamma_function); |
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} |
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|
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//-------------------------------------------------------------------- |
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void reset(); |
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void filling_rule(filling_rule_e filling_rule); |
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void clip_box(double x1, double y1, double x2, double y2); |
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void reset_clipping(); |
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|
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//-------------------------------------------------------------------- |
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template<class GammaF> void gamma(const GammaF& gamma_function) |
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{ |
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int i; |
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for(i = 0; i < aa_num; i++) |
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{ |
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m_gamma[i] = int(floor(gamma_function(double(i) / aa_mask) * aa_mask + 0.5)); |
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} |
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} |
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//-------------------------------------------------------------------- |
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unsigned apply_gamma(unsigned cover) const |
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{ |
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return m_gamma[cover]; |
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} |
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|
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//-------------------------------------------------------------------- |
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void add_vertex(double x, double y, unsigned cmd); |
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void move_to(int x, int y); |
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void line_to(int x, int y); |
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void close_polygon(); |
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void move_to_d(double x, double y); |
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void line_to_d(double x, double y); |
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//-------------------------------------------------------------------- |
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int min_x() const { return m_outline.min_x(); } |
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int min_y() const { return m_outline.min_y(); } |
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int max_x() const { return m_outline.max_x(); } |
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int max_y() const { return m_outline.max_y(); } |
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//-------------------------------------------------------------------- |
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AGG_INLINE unsigned calculate_alpha(int area) const |
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{ |
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int cover = area >> (poly_base_shift*2 + 1 - aa_shift); |
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|
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if(cover < 0) cover = -cover; |
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if(m_filling_rule == fill_even_odd) |
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{ |
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cover &= aa_2mask; |
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if(cover > aa_num) |
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{ |
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cover = aa_2num - cover; |
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} |
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} |
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if(cover > aa_mask) cover = aa_mask; |
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return m_gamma[cover]; |
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} |
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//-------------------------------------------------------------------- |
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void sort() |
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{ |
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m_outline.cells(); |
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} |
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//-------------------------------------------------------------------- |
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bool rewind_scanlines() |
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{ |
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close_polygon(); |
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m_iterator.cells = m_outline.cells(); |
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if(m_outline.num_cells() == 0) |
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{ |
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return false; |
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} |
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m_iterator.cover = 0; |
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m_iterator.last_y = (*m_iterator.cells)->y; |
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return true; |
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} |
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//-------------------------------------------------------------------- |
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template<class Scanline> bool sweep_scanline(Scanline& sl) |
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{ |
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sl.reset_spans(); |
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for(;;) |
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{ |
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const cell_aa* cur_cell = *m_iterator.cells; |
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if(cur_cell == 0) return false; |
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++m_iterator.cells; |
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m_iterator.last_y = cur_cell->y; |
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for(;;) |
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{ |
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int coord = cur_cell->packed_coord; |
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int area = cur_cell->area; |
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int last_x = cur_cell->x; |
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m_iterator.cover += cur_cell->cover; |
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//accumulate all cells with the same coordinates |
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for(; (cur_cell = *m_iterator.cells) != 0; ++m_iterator.cells) |
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{ |
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if(cur_cell->packed_coord != coord) break; |
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area += cur_cell->area; |
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m_iterator.cover += cur_cell->cover; |
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} |
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int alpha; |
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if(cur_cell == 0 || cur_cell->y != m_iterator.last_y) |
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{ |
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if(area) |
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{ |
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alpha = calculate_alpha((m_iterator.cover << (poly_base_shift + 1)) - area); |
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if(alpha) |
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{ |
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sl.add_cell(last_x, alpha); |
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} |
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++last_x; |
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} |
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break; |
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} |
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++m_iterator.cells; |
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if(area) |
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{ |
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alpha = calculate_alpha((m_iterator.cover << (poly_base_shift + 1)) - area); |
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if(alpha) |
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{ |
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sl.add_cell(last_x, alpha); |
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} |
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++last_x; |
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} |
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if(cur_cell->x > last_x) |
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{ |
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alpha = calculate_alpha(m_iterator.cover << (poly_base_shift + 1)); |
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if(alpha) |
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{ |
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sl.add_span(last_x, cur_cell->x - last_x, alpha); |
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} |
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} |
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} |
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if(sl.num_spans()) |
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{ |
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sl.finalize(m_iterator.last_y); |
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break; |
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} |
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} |
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return true; |
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} |
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//-------------------------------------------------------------------- |
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bool hit_test(int tx, int ty); |
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//-------------------------------------------------------------------- |
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void add_xy(const double* x, const double* y, unsigned n) |
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{ |
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if(n > 2) |
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{ |
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move_to_d(*x++, *y++); |
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--n; |
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do |
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{ |
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line_to_d(*x++, *y++); |
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} |
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while(--n); |
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} |
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} |
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//------------------------------------------------------------------- |
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template<class VertexSource> |
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void add_path(VertexSource& vs, unsigned id=0) |
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{ |
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double x; |
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double y; |
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unsigned cmd; |
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vs.rewind(id); |
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while(!is_stop(cmd = vs.vertex(&x, &y))) |
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{ |
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add_vertex(x, y, cmd); |
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} |
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} |
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private: |
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//-------------------------------------------------------------------- |
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// Disable copying |
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rasterizer_scanline_aa(const rasterizer_scanline_aa<XScale, AA_Shift>&); |
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const rasterizer_scanline_aa<XScale, AA_Shift>& |
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operator = (const rasterizer_scanline_aa<XScale, AA_Shift>&); |
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//-------------------------------------------------------------------- |
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void move_to_no_clip(int x, int y); |
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void line_to_no_clip(int x, int y); |
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void close_polygon_no_clip(); |
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void clip_segment(int x, int y); |
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private: |
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outline_aa m_outline; |
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int m_gamma[aa_num]; |
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filling_rule_e m_filling_rule; |
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int m_clipped_start_x; |
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int m_clipped_start_y; |
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int m_start_x; |
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int m_start_y; |
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int m_prev_x; |
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int m_prev_y; |
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unsigned m_prev_flags; |
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unsigned m_status; |
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rect m_clip_box; |
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bool m_clipping; |
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iterator m_iterator; |
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}; |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::reset() |
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{ |
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m_outline.reset(); |
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m_status = status_initial; |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::filling_rule(filling_rule_e filling_rule) |
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{ |
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m_filling_rule = filling_rule; |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::clip_box(double x1, double y1, double x2, double y2) |
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{ |
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reset(); |
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m_clip_box = rect(poly_coord(x1), poly_coord(y1), |
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poly_coord(x2), poly_coord(y2)); |
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m_clip_box.normalize(); |
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m_clipping = true; |
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} |
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|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::reset_clipping() |
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{ |
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reset(); |
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m_clipping = false; |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::move_to_no_clip(int x, int y) |
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{ |
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if(m_status == status_line_to) |
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{ |
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close_polygon_no_clip(); |
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} |
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m_outline.move_to(x * XScale, y); |
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m_clipped_start_x = x; |
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m_clipped_start_y = y; |
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m_status = status_line_to; |
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} |
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|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::line_to_no_clip(int x, int y) |
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{ |
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if(m_status != status_initial) |
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{ |
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m_outline.line_to(x * XScale, y); |
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m_status = status_line_to; |
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} |
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} |
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|
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|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::close_polygon_no_clip() |
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{ |
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if(m_status == status_line_to) |
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{ |
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m_outline.line_to(m_clipped_start_x * XScale, m_clipped_start_y); |
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m_status = status_closed; |
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} |
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} |
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|
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|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::clip_segment(int x, int y) |
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{ |
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unsigned flags = clipping_flags(x, y, m_clip_box); |
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if(m_prev_flags == flags) |
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{ |
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if(flags == 0) |
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{ |
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if(m_status == status_initial) |
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{ |
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move_to_no_clip(x, y); |
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} |
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else |
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{ |
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line_to_no_clip(x, y); |
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} |
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} |
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} |
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else |
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{ |
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int cx[4]; |
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int cy[4]; |
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unsigned n = clip_liang_barsky(m_prev_x, m_prev_y, |
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x, y, |
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m_clip_box, |
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cx, cy); |
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const int* px = cx; |
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const int* py = cy; |
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while(n--) |
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{ |
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if(m_status == status_initial) |
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{ |
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move_to_no_clip(*px++, *py++); |
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} |
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else |
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{ |
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line_to_no_clip(*px++, *py++); |
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} |
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} |
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} |
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m_prev_flags = flags; |
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m_prev_x = x; |
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m_prev_y = y; |
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} |
|
|
|
|
|
|
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//------------------------------------------------------------------------ |
|
template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::add_vertex(double x, double y, unsigned cmd) |
|
{ |
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if(is_close(cmd)) |
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{ |
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close_polygon(); |
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} |
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else |
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{ |
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if(is_move_to(cmd)) |
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{ |
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move_to(poly_coord(x), poly_coord(y)); |
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} |
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else |
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{ |
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if(is_vertex(cmd)) |
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{ |
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line_to(poly_coord(x), poly_coord(y)); |
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} |
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} |
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} |
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} |
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|
|
|
|
|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::move_to(int x, int y) |
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{ |
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if(m_clipping) |
|
{ |
|
if(m_outline.sorted()) |
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{ |
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reset(); |
|
} |
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if(m_status == status_line_to) |
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{ |
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close_polygon(); |
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} |
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m_prev_x = m_start_x = x; |
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m_prev_y = m_start_y = y; |
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m_status = status_initial; |
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m_prev_flags = clipping_flags(x, y, m_clip_box); |
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if(m_prev_flags == 0) |
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{ |
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move_to_no_clip(x, y); |
|
} |
|
} |
|
else |
|
{ |
|
move_to_no_clip(x, y); |
|
} |
|
} |
|
|
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::line_to(int x, int y) |
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{ |
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if(m_clipping) |
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{ |
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clip_segment(x, y); |
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} |
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else |
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{ |
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line_to_no_clip(x, y); |
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} |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::close_polygon() |
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{ |
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if(m_clipping) |
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{ |
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clip_segment(m_start_x, m_start_y); |
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} |
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close_polygon_no_clip(); |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::move_to_d(double x, double y) |
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{ |
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move_to(poly_coord(x), poly_coord(y)); |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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void rasterizer_scanline_aa<XScale, AA_Shift>::line_to_d(double x, double y) |
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{ |
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line_to(poly_coord(x), poly_coord(y)); |
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} |
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//------------------------------------------------------------------------ |
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template<unsigned XScale, unsigned AA_Shift> |
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bool rasterizer_scanline_aa<XScale, AA_Shift>::hit_test(int tx, int ty) |
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{ |
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close_polygon(); |
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const cell_aa* const* cells = m_outline.cells(); |
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if(m_outline.num_cells() == 0) return false; |
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int cover = 0; |
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const cell_aa* cur_cell = *cells++; |
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for(;;) |
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{ |
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int alpha; |
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int coord = cur_cell->packed_coord; |
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int x = cur_cell->x; |
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int y = cur_cell->y; |
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if(y > ty) return false; |
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int area = cur_cell->area; |
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cover += cur_cell->cover; |
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while((cur_cell = *cells++) != 0) |
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{ |
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if(cur_cell->packed_coord != coord) break; |
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area += cur_cell->area; |
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cover += cur_cell->cover; |
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} |
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if(area) |
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{ |
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alpha = calculate_alpha((cover << (poly_base_shift + 1)) - area); |
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if(alpha) |
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{ |
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if(tx == x && ty == y) return true; |
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} |
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x++; |
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} |
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if(!cur_cell) break; |
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if(cur_cell->x > x) |
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{ |
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alpha = calculate_alpha(cover << (poly_base_shift + 1)); |
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if(alpha) |
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{ |
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if(ty == y && tx >= x && tx <= cur_cell->x) return true; |
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} |
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} |
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} |
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return false; |
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} |
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} |
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#endif |
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