Merge pull request #1371 from siliconninja/issue_1277

Fix coordinate precision to 8 decimal places to reduce file size

src/control/settings/Settings.cpp

@@ -780,7 +780,8 @@ xmlNodePtr Settings::savePropertyDouble(const gchar* key, double value, xmlNodeP
 	XOJ_CHECK_TYPE(Settings);
 
 	char text[G_ASCII_DTOSTR_BUF_SIZE];
-	g_ascii_dtostr( text, G_ASCII_DTOSTR_BUF_SIZE, value);	//  g_ascii_ version uses C locale always.
+	//  g_ascii_ version uses C locale always.
+	g_ascii_formatd(text, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, value);
 	xmlNodePtr xmlNode = saveProperty(key, text, parent);
 	return xmlNode;
 }
@@ -1043,7 +1044,8 @@ void Settings::save()
 	xmlSetProp(xmlFont, (const xmlChar*) "font", (const xmlChar*) this->font.getName().c_str());
 
 	char sSize[G_ASCII_DTOSTR_BUF_SIZE];
-	g_ascii_dtostr( sSize, G_ASCII_DTOSTR_BUF_SIZE, this->font.getSize());	//no locale
+
+	g_ascii_formatd(sSize, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, this->font.getSize());  // no locale
 	xmlSetProp(xmlFont, (const xmlChar*) "size", (const xmlChar*) sSize);
 
 
@@ -1100,7 +1102,7 @@ void Settings::saveData(xmlNodePtr root, string name, SElement& elem)
 			type = "double";
 
 			char tmp[G_ASCII_DTOSTR_BUF_SIZE];
-			g_ascii_dtostr( tmp, G_ASCII_DTOSTR_BUF_SIZE, attrib.dValue);
+			g_ascii_formatd(tmp, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, attrib.dValue);
 			value = tmp;
 		}
 		else if (attrib.type == ATTRIBUTE_TYPE_INT_HEX)

src/control/xml/DoubleArrayAttribute.cpp

@@ -1,4 +1,5 @@
 #include "DoubleArrayAttribute.h"
+#include "Util.h"
 
 DoubleArrayAttribute::DoubleArrayAttribute(const char* name, double* values, int count) : XMLAttribute(name)
 {
@@ -25,15 +26,16 @@ void DoubleArrayAttribute::writeOut(OutputStream* out)
 	if (this->count > 0)
 	{
 		char str[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( str, G_ASCII_DTOSTR_BUF_SIZE, this->values[0]);	//  g_ascii_ version uses C locale always.
+		// g_ascii_ version uses C locale always.
+		g_ascii_formatd(str, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, this->values[0]);
 		out->write(str);
-	}
 
-	for (int i = 1; i < this->count; i++)
-	{
-		char str[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( str, G_ASCII_DTOSTR_BUF_SIZE, this->values[i]);
-		out->write(" ");
-		out->write(str);
+		for (int i = 1; i < this->count; i++)
+		{
+			// g_ascii_ version uses C locale always.
+			g_ascii_formatd(str, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, this->values[i]);
+			out->write(" ");
+			out->write(str);
+		}
 	}
 }

src/control/xml/DoubleAttribute.cpp

@@ -1,4 +1,5 @@
 #include "DoubleAttribute.h"
+#include "Util.h"
 
 DoubleAttribute::DoubleAttribute(const char* name, double value) : XMLAttribute(name)
 {
@@ -17,7 +18,8 @@ void DoubleAttribute::writeOut(OutputStream* out)
 	XOJ_CHECK_TYPE(DoubleAttribute);
 
 	char str[G_ASCII_DTOSTR_BUF_SIZE];
-	g_ascii_dtostr( str, G_ASCII_DTOSTR_BUF_SIZE, value);	//  g_ascii_ version uses C locale always.
+	// g_ascii_ version uses C locale always.
+	g_ascii_formatd(str, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, value);
 	out->write(str);
 
 }

src/control/xml/XmlPointNode.cpp

@@ -1,3 +1,4 @@
+#include "Util.h"
 #include "XmlPointNode.h"
 
 XmlPointNode::XmlPointNode(const char* tag)
@@ -47,15 +48,10 @@ void XmlPointNode::writeOut(OutputStream* out)
 		{
 			out->write(" ");
 		}
-		char tmpX[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( tmpX, G_ASCII_DTOSTR_BUF_SIZE, p->x);
-		char tmpY[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( tmpY, G_ASCII_DTOSTR_BUF_SIZE, p->y);
 
-		char* tmp = g_strdup_printf("%s %s", tmpX, tmpY);
-		out->write(tmp);
-		g_free(tmp);
-		
+		gchar coordinateStr[Util::PRECISION_FORMAT_BUFF_LEN];
+		Util::getCoordinateString(coordinateStr, Util::PRECISION_FORMAT_BUFF_LEN, p->x, p->y);
+		out->write(coordinateStr);
 	}
 
 	out->write("</");

src/control/xml/XmlStrokeNode.cpp

@@ -1,3 +1,4 @@
+#include "Util.h"
 #include "XmlStrokeNode.h"
 
 XmlStrokeNode::XmlStrokeNode(const char* tag) : XmlNode(tag)
@@ -65,17 +66,17 @@ void XmlStrokeNode::writeOut(OutputStream* out)
 	writeAttributes(out);
 
 	out->write(" width=\"");
-	
-	char tmp[G_ASCII_DTOSTR_BUF_SIZE];
-	g_ascii_dtostr( tmp, G_ASCII_DTOSTR_BUF_SIZE,width);	//  g_ascii_ version uses C locale always.
-	out->write(tmp);
+
+	char widthStr[G_ASCII_DTOSTR_BUF_SIZE];
+	// g_ascii_ version uses C locale always.
+	g_ascii_formatd(widthStr, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, width);
+	out->write(widthStr);
 
 	for (int i = 0; i < widthsLength; i++)
 	{
-		char tmp[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( tmp, G_ASCII_DTOSTR_BUF_SIZE,widths[i]);
+		g_ascii_formatd(widthStr, G_ASCII_DTOSTR_BUF_SIZE, Util::PRECISION_FORMAT_STRING, widths[i]);
 		out->write(" ");
-		out->write(tmp);
+		out->write(widthStr);
 	}
 
 	out->write("\"");
@@ -88,26 +89,15 @@ void XmlStrokeNode::writeOut(OutputStream* out)
 	{
 		out->write(">");
 
-		char tmpX[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( tmpX, G_ASCII_DTOSTR_BUF_SIZE, points[0].x);
-		char tmpY[G_ASCII_DTOSTR_BUF_SIZE];
-		g_ascii_dtostr( tmpY, G_ASCII_DTOSTR_BUF_SIZE, points[0].y);
-
-		char* tmp = g_strdup_printf("%s %s", tmpX, tmpY);
-		out->write(tmp);
-		g_free(tmp);
+		gchar coordinateStr[Util::PRECISION_FORMAT_BUFF_LEN];
+		Util::getCoordinateString(coordinateStr, Util::PRECISION_FORMAT_BUFF_LEN, points[0].x, points[0].y);
+		out->write(coordinateStr);
 
 		for (int i = 1; i < this->pointsLength; i++)
 		{
-			char tmpX[G_ASCII_DTOSTR_BUF_SIZE];
-			g_ascii_dtostr( tmpX, G_ASCII_DTOSTR_BUF_SIZE, points[i].x);
-			char tmpY[G_ASCII_DTOSTR_BUF_SIZE];
-			g_ascii_dtostr( tmpY, G_ASCII_DTOSTR_BUF_SIZE, points[i].y);
-
-			char* tmp = g_strdup_printf("%s %s", tmpX, tmpY);
+			Util::getCoordinateString(coordinateStr, Util::PRECISION_FORMAT_BUFF_LEN, points[i].x, points[i].y);
 			out->write(" ");
-			out->write(tmp);
-			g_free(tmp);
+			out->write(coordinateStr);
 		}
 
 		out->write("</");

src/util/Util.cpp

@@ -170,3 +170,8 @@ gboolean Util::paintBackgroundWhite(GtkWidget* widget, cairo_t* cr, void*)
 	return false;
 }
 
+gchar* Util::getCoordinateString(gchar* buff, gulong buffLen, double xVal, double yVal)
+{
+	g_snprintf(buff, buffLen, Util::PRECISION_FORMAT_STRING_XY, xVal, yVal);
+	return buff;
+}

src/util/Util.h

@@ -53,6 +53,19 @@ void execInUiThread(std::function<void()>&& callback);
 
 gboolean paintBackgroundWhite(GtkWidget* widget, cairo_t* cr, void* unused);
 
+/**
+ * Format coordinates to use 8 digits of precision https://m.xkcd.com/2170/
+ * This function works like g_ascii_formatd in that it stores the result in buff, and
+ * also returns the result.
+ */
+extern gchar* getCoordinateString(gchar* buff, gulong buffLen, double xVal, double yVal);
+
+constexpr const gchar* PRECISION_FORMAT_STRING = "%.8f";
+
+constexpr const gchar* PRECISION_FORMAT_STRING_XY = "%.8f %.8f";  // note the space delimiter
+
+constexpr const int PRECISION_FORMAT_BUFF_LEN = G_ASCII_DTOSTR_BUF_SIZE * 2 + 1;
+
 }  // namespace Util
 
-static const size_t npos = std::numeric_limits<size_t>::max();
+static const size_t npos = std::numeric_limits<size_t>::max();