Plugin for cycling through a color list

Plugin for cycling through a color list

plugins/ColorCycle/main.lua

@@ -0,0 +1,38 @@
+-- Register all Toolbar actions and intialize all UI stuff
+function initUi()
+  app.registerUi({["menu"] = "Cycle through color list", ["callback"] = "cycle", ["accelerator"] = "<Alt>c"});
+  -- if you want to have multiple color lists you must use the app.registerUi function multiple times
+  -- with different callback functions and accelerators
+end
+
+-- Predefined colors copied from LoadHandlerHelper.cpp 
+-- modify to your needs 
+local colorList = { 
+  {"black", 0x000000},  
+  {"green", 0x008000},
+  {"lightblue", 0x00c0ff}, 
+  {"lightgreen", 0x00ff00}, 
+  {"blue", 0x3333cc},      
+  {"gray", 0x808080},   
+  {"red", 0xff0000},        
+  {"magenta", 0xff00ff},
+  {"orange", 0xff8000}, 
+  {"yellow", 0xffff00},    
+  {"white", 0xffffff}
+}
+
+-- start with first color
+local currentColor = 0 
+
+function cycle()
+  if (currentColor < #colorList) then
+    currentColor = currentColor + 1
+  else
+    currentColor = 1
+  end
+  -- apply color to currently used tool and allow coloring of elements from selections
+  app.changeToolColor({["color"] = colorList[currentColor][2], ["selection"] = true})
+  -- use app.changeColor({["color"] = colorList[currentColor][2], ["tool"] = "pen""}) 
+  -- instead if you only want to change pen color
+  -- similarly if you want to change hilighter color or the color from another tool with color capabilities.
+end

plugins/ColorCycle/plugin.ini

@@ -0,0 +1,15 @@
+[about]
+## Author / Copyright notice
+author=Roland Lötscher
+
+description=Cycling through color list.
+
+## If the plugin is packed with Xournal++, use
+## <xournalpp> then it gets the same version number
+version=<xournalpp>
+
+[default]
+enabled=false
+
+[plugin]
+mainfile=main.lua

src/plugin/luapi_application.h

@@ -14,6 +14,7 @@
 
 #include "control/Control.h"
 #include "control/PageBackgroundChangeController.h"
+#include "control/Tool.h"
 #include "control/pagetype/PageTypeHandler.h"
 
 #include "StringUtils.h"
@@ -218,7 +219,7 @@ static int applib_uiActionSelected(lua_State* L) {
 }
 
 /**
- * Select UI action
+ * Change page background
  */
 static int applib_changeCurrentPageBackground(lua_State* L) {
     PageType pt;
@@ -233,6 +234,79 @@ static int applib_changeCurrentPageBackground(lua_State* L) {
     return 1;
 }
 
+/**
+ * Change color of a specified tool or of the current tool
+ */
+static int applib_changeToolColor(lua_State* L) {
+
+    // discard any extra arguments passed in
+    lua_settop(L, 1);
+    luaL_checktype(L, 1, LUA_TTABLE);
+
+    lua_getfield(L, 1, "selection"); /* either true or false, for changing selection color
+                                       defaults to false*/
+    lua_getfield(L, 1, "tool");      /* "pen", "hilighter", "text"
+                                      "select_rect", "select_object", "select_region"
+                                      if omitted, current Tool is used */
+    lua_getfield(L, 1, "color");     // an RGB hex code defining the color
+    // stack now has following:
+    //    1 = {["color"] = 0xff00ff, ["tool"] = "PEN", ["selection"] = false}
+    //   -3 = false
+    //   -2 = "pen"
+    //   -1 = 0xff0077
+
+    Plugin* plugin = Plugin::getPluginFromLua(L);
+    Control* ctrl = plugin->getControl();
+    ToolHandler* toolHandler = ctrl->getToolHandler();
+
+    bool selection = false;
+    if (lua_isboolean(L, -3)) {
+        selection = lua_toboolean(L, -3);
+    } else if (!lua_isnil(L, -3)) {
+        g_warning(""
+                  "selection"
+                  " key should be a boolean value (or nil)");
+    }
+
+    ToolType toolType = toolHandler->getToolType();
+    const char* toolStr = luaL_optstring(L, -2, nullptr);
+    if (toolStr != nullptr) {
+        toolType = toolTypeFromString(StringUtils::toLowerCase(toolStr));
+    }
+
+    if (toolType == TOOL_NONE) {
+        g_warning("tool \"%s\" is not valid or no tool has been selected", toolTypeToString(toolType).c_str());
+        lua_pop(L, 3);
+        return 0;
+    }
+
+    int color = 0x000000;
+    if (lua_isinteger(L, -1)) {
+        color = lua_tointeger(L, -1);
+        if (color < 0x000000 || color > 0xffffff) {
+            g_warning("Color 0x%x is no valid RGB color. ", color);
+            return 0;
+        }
+    } else if (!lua_isnil(L, -1)) {
+        g_warning(" "
+                  "color"
+                  " key should be an RGB hex code in the form 0xRRGGBB (or nil)");
+    }
+
+    Tool& tool = toolHandler->getTool(toolType);
+
+    if (tool.hasCapability(TOOL_CAP_COLOR)) {
+        tool.setColor(color);
+        ctrl->toolColorChanged(selection);
+    } else {
+        g_warning("tool \"%s\" has no color capability", toolTypeToString(toolType).c_str());
+    }
+
+    // Make sure to remove all vars which are put to the stack before!
+    lua_pop(L, 3);
+
+    return 1;
+}
 
 static const luaL_Reg applib[] = {{"msgbox", applib_msgbox},
                                   {"registerUi", applib_registerUi},
@@ -240,6 +314,7 @@ static const luaL_Reg applib[] = {{"msgbox", applib_msgbox},
                                   {"uiActionSelected", applib_uiActionSelected},
                                   {"changeCurrentPageBackground", applib_changeCurrentPageBackground},
                                   {"saveAs", applib_saveAs},
+                                  {"changeToolColor", applib_changeToolColor},
 
                                   // Placeholder
                                   //	{"MSG_BT_OK", nullptr},