Move everything that deals with images directly to an Image class

Image.cpp

@@ -0,0 +1,106 @@
+#include <cstdio>
+#include <cerrno>
+#include <cstring>
+#include <iostream>
+#include <sstream>
+#include <stdexcept>
+#include <gd.h>
+#include <gdfontmb.h>
+
+#include "Image.h"
+
+#ifndef NDEBUG
+#define SIZECHECK(x, y) do { \
+		if((x) < 0 || (x) >= m_width) \
+			throw std::out_of_range("sizecheck x"); \
+		if((y) < 0 || (y) >= m_height) \
+			throw std::out_of_range("sizecheck y"); \
+	} while(0)
+#else
+#define SIZECHECK(x, y) do {} while(0)
+#endif
+
+// BGRA but with inverted alpha
+
+static inline int color2int(Color c)
+{
+	u8 a = 255 - c.a;
+	return (a << 24) | (c.r << 16) | (c.g << 8) | c.b;
+}
+
+static inline Color int2color(int c)
+{
+	Color c2;
+	u8 a;
+	c2.b = c & 0xff;
+	c2.g = (c >> 8) & 0xff;
+	c2.r = (c >> 16) & 0xff;
+	a = (c >> 24) & 0xff;
+	c2.a = 255 - a;
+	return c2;
+}
+
+
+Image::Image(int width, int height) :
+	m_width(width), m_height(height), m_image(NULL)
+{
+	m_image = gdImageCreateTrueColor(m_width, m_height);
+}
+
+Image::~Image()
+{
+	gdImageDestroy(m_image);
+}
+
+void Image::setPixel(int x, int y, const Color &c)
+{
+	SIZECHECK(x, y);
+	m_image->tpixels[y][x] = color2int(c);
+}
+
+Color Image::getPixel(int x, int y)
+{
+#ifndef NDEBUG
+	if(x < 0 || x > m_width || y < 0 || y > m_height)
+		throw std::out_of_range("sizecheck");
+#endif
+	return int2color(m_image->tpixels[y][x]);
+}
+
+void Image::drawLine(int x1, int y1, int x2, int y2, const Color &c)
+{
+	SIZECHECK(x1, y1);
+	SIZECHECK(x2, y2);
+	gdImageLine(m_image, x1, y1, x2, y2, color2int(c));
+}
+
+void Image::drawText(int x, int y, const std::string &s, const Color &c)
+{
+	SIZECHECK(x, y);
+	gdImageString(m_image, gdFontGetMediumBold(), x, y, (unsigned char*) s.c_str(), color2int(c));
+}
+
+void Image::drawFilledRect(int x, int y, int w, int h, const Color &c)
+{
+	SIZECHECK(x, y);
+	SIZECHECK(x + w - 1, y + h - 1);
+	gdImageFilledRectangle(m_image, x, y, x + w - 1, y + h - 1, color2int(c));
+}
+
+void Image::drawCircle(int x, int y, int diameter, const Color &c)
+{
+	SIZECHECK(x, y);
+	gdImageArc(m_image, x, y, diameter, diameter, 0, 360, color2int(c));
+}
+
+void Image::save(const std::string &filename)
+{
+	FILE *f = fopen(filename.c_str(), "wb");
+	if(!f) {
+		std::ostringstream oss;
+		oss << "Error writing image file: " << std::strerror(errno);
+		throw std::runtime_error(oss.str());
+	}
+	gdImagePng(m_image, f); // other formats?
+	fclose(f);
+}