test for SDL_image

sdlimagetest.cpp

/*
g++ sdlimagetest.cpp -framework SDL -framework SDLimage -I /Library/Frameworks/SDL.framework/Headers -I /Library/Frameworks/SDLimage.framework/Headers -o sdlimagetest 
 */

#include <SDL.h>
#include <SDL_image.h>
#include <assert.h>
#include <sstream>
#include <string>
#include <iostream>

using namespace std;

Uint32 GetPixel(SDL_Surface* s, int x, int y) {
	char* addr = (char*)s->pixels + y * s->pitch + x * s->format->BytesPerPixel;
	switch(s->format->BytesPerPixel) {
		case 4: return *(Uint32*)addr;
		case 3: return
			Uint32(*(Uint8*)addr) +
			(Uint32(*(Uint8*)(addr+1)) << 8) +
			(Uint32(*(Uint8*)(addr+2)) << 16);
		case 2: return *(Uint16*)addr;
		case 1: return (Uint8)*addr;
		default: assert(false);
	}
}

void DumpPixelFormat(const SDL_PixelFormat* format) { 
	std::ostringstream str; 
	str << "PixelFormat:" << std::endl 
	<< "  BitsPerPixel: " << (int)format->BitsPerPixel << "," 
	<< "  BytesPerPixel: " << (int)format->BytesPerPixel << std::endl 
	<< "  R/G/B/A mask: " << std::hex 
	<< (uint)format->Rmask << "/" 
	<< (uint)format->Gmask << "/" 
	<< (uint)format->Bmask << "/" 
	<< (uint)format->Amask << std::endl 
	<< "  R/G/B/A loss: " 
	<< (uint)format->Rloss << "/" 
	<< (uint)format->Gloss << "/" 
	<< (uint)format->Bloss << "/" 
	<< (uint)format->Aloss << std::endl 
	<< "  Colorkey: " << std::hex << (uint)format->colorkey << "," 
	<< "  Alpha: " << std::dec << (int)format->alpha; 
	cout << str.str() << endl; 
} 

void DumpSurface(SDL_Surface* s) { 
	DumpPixelFormat(s->format); 
	for(int y = 0; y < std::min(10, s->h); ++y) { 
		for(int x = 0; x < std::min(10, s->w); ++x) 
			printf(" %.8X", GetPixel(s, x, y)); 
		printf("\n"); 
	} 
}

#undef main

char imgdata[] = {
	0x89,0x50,0x4E,0x47,0x0D,0x0A,0x1A,0x0A,0x00,0x00,
	0x00,0x0D,0x49,0x48,0x44,0x52,0x00,0x00,0x00,0x01,
	0x00,0x00,0x00,0x0D,0x08,0x06,0x00,0x00,0x01,0x1F,
	0xD0,0x34,0x64,0x00,0x00,0x00,0x01,0x73,0x52,0x47,
	0x42,0x00,0xAE,0xCE,0x1C,0xE9,0x00,0x00,0x00,0x06,
	0x62,0x4B,0x47,0x44,0x00,0xFF,0x00,0xFF,0x00,0xFF,
	0xA0,0xBD,0xA7,0x93,0x00,0x00,0x00,0x09,0x70,0x48,
	0x59,0x73,0x00,0x00,0x0B,0x13,0x00,0x00,0x0B,0x13,
	0x01,0x00,0x9A,0x9C,0x18,0x00,0x00,0x00,0x07,0x74,
	0x49,0x4D,0x45,0x07,0xDC,0x01,0x02,0x0F,0x3A,0x2B,
	0xBC,0x08,0xF7,0xCB,0x00,0x00,0x00,0x16,0x49,0x44,
	0x41,0x54,0x08,0xD7,0x63,0x60,0x60,0xF8,0xFF,0x9F,
	0x89,0x01,0x02,0x30,0x58,0xD8,0xB8,0x68,0x04,0x00,
	0x6A,0xEE,0x08,0x0B,0xBF,0x8A,0x7D,0x51,0x00,0x00,
	0x00,0x00,0x49,0x45,0x4E,0x44,0xAE,0x42,0x60,0x82,
};

int main() {
	SDL_Surface* img = IMG_Load_RW(SDL_RWFromMem(imgdata, sizeof(imgdata)), true);
	assert(img != NULL);
	
	DumpSurface(img);
	
	SDL_FreeSurface(img);
	return 0;
}