minetestmapper/Image.cpp

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C++
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#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) check_bounds((x), (y), m_width, m_height)
#else
#define SIZECHECK(x, y) do {} while(0)
#endif
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// ARGB but with inverted alpha
static inline int color2int(const Color &c)
{
u8 a = (255 - c.a) * gdAlphaMax / 255;
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*255 / gdAlphaMax);
return c2;
}
#ifndef NDEBUG
static inline void check_bounds(int x, int y, int width, int height)
{
if(x < 0 || x >= width) {
std::ostringstream oss;
oss << "Access outside image bounds (x), 0 < "
<< x << " < " << width << " is false.";
throw std::out_of_range(oss.str());
}
if(y < 0 || y >= height) {
std::ostringstream oss;
oss << "Access outside image bounds (y), 0 < "
<< y << " < " << height << " is false.";
throw std::out_of_range(oss.str());
}
}
#endif
Image::Image(int width, int height) :
m_width(width), m_height(height), m_image(NULL)
{
SIZECHECK(0, 0);
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)
{
SIZECHECK(x, y);
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)
{
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#if (GD_MAJOR_VERSION == 2 && GD_MINOR_VERSION == 1 && GD_RELEASE_VERSION >= 1) || (GD_MAJOR_VERSION == 2 && GD_MINOR_VERSION > 1) || GD_MAJOR_VERSION > 2
const char *f = filename.c_str();
if (gdSupportsFileType(f, 1) == GD_FALSE)
throw std::runtime_error("Image format not supported by gd");
if (gdImageFile(m_image, f) == GD_FALSE)
throw std::runtime_error("Error saving image");
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#else
if (filename.compare(filename.length() - 4, 4, ".png") != 0)
throw std::runtime_error("Only PNG is supported");
FILE *f = fopen(filename.c_str(), "wb");
if (!f) {
std::ostringstream oss;
oss << "Error opening image file: " << std::strerror(errno);
throw std::runtime_error(oss.str());
}
gdImagePng(m_image, f);
fclose(f);
#endif
}