Targa.c

// Licenced under LGPL: www.gnu.org/copyleft/lesser.html

1. include <stdlib.h>
2. include <stdio.h>
3. include <string.h>

main() {

// Create a new targa image in memory char* newImage(int width, int height) { char* image = calloc(18+4*width*height+26,sizeof(char)); strcpy(image+18+4*width*height+8,"TRUEVISION-XFILE."); image[2] = 2; image[12] = width & 0xff; image[13] = (width & 0xff00) >> 8; image[14] = height & 0xff; image[15] = (height & 0xff00) >> 8; image[16] = ' '; image[17] = 8; return image; }

int getSize(unsigned char* image) { int width = (image[13]<<8)+image[12]; int height = (image[15]<<8)+image[14]; return 18+4*width*height+26; }

char* getOffset(unsigned char* image, int x, int y) { int width = (image[13]<<8)+image[12]; return image+18+4*(x+y*width); }

int getPixel(char* image, int x, int y) { return *getOffset(image,x,y); }

// Set pixel at x,y to colour allowing for alpha void setPixel(char* image, int x, int y, int colour) { int i, col[3], a = colour >> 24; col[0] = (colour & 0xff0000) >> 16; col[1] = (colour & 0xff00) >> 8; col[2] = colour & 0xff; unsigned char* pix = getOffset(image,x,y); for (i=0; i<3; i++) pix[i] = (col[i]*a/255+pix[i]*(255-a)/255); }

void fillRect(char* image, int x1, int y1, int x2, int y2, int colour) { int x,y; for (y=y1; y<y2; y++) for (x=x1; x<x2; x++) setPixel(image,x,y,colour); }

// Create test a image char* image = newImage(100,200); fillRect(image,10,20,30,40,0xff0000ff); fillRect(image,20,30,40,50,0x80ff0000);

// Write test image to file and convert to jpeg int fd = creat("/var/www/wiki/targa.tga",0x755); write(fd,image,getSize(image)); system("cjpeg /var/www/wiki/targa.tga > /var/www/wiki/targa.jpg");

}