hello_image_sdl.c

#include <stdio.h>
#include <SDL/SDL.h>
#include <SDL/SDL_image.h>
#include <assert.h>
#include <emscripten.h>
#include <unistd.h>

int testImage(SDL_Surface* screen, const char* fileName) {
  SDL_Surface *image = IMG_Load(fileName);
  if (!image)
  {
     printf("IMG_Load: %s\n", IMG_GetError());
     return 0;
  }
  assert(image->format->BitsPerPixel == 32);
  assert(image->format->BytesPerPixel == 4);
  assert(image->pitch == 4*image->w);
  int result = image->w;

  SDL_BlitSurface (image, NULL, screen, NULL);
  SDL_FreeSurface (image);

  return result;
}

int main() {
  SDL_Init(SDL_INIT_VIDEO);
  SDL_Surface *screen = SDL_SetVideoMode(600, 450, 32, SDL_SWSURFACE);

  int result = 0;

  result |= testImage(screen, "screenshot.jpg"); // absolute path
  assert(result != 0);

  SDL_Flip(screen);

  printf("you should see an image.\n");

  SDL_Quit();

  return 0;
}

out.js

function _testImage($screen,$fileName) {
 $screen = $screen|0;
 $fileName = $fileName|0;
 var $0 = 0, $1 = 0, $10 = 0, $11 = 0, $12 = 0, $13 = 0, $14 = 0, $15 = 0, $16 = 0, $17 = 0, $18 = 0, $19 = 0, $2 = 0, $20 = 0, $21 = 0, $22 = 0, $23 = 0, $24 = 0, $25 = 0, $26 = 0;
 var $27 = 0, $28 = 0, $29 = 0, $3 = 0, $30 = 0, $31 = 0, $32 = 0, $33 = 0, $34 = 0, $35 = 0, $36 = 0, $37 = 0, $4 = 0, $5 = 0, $6 = 0, $7 = 0, $8 = 0, $9 = 0, $image = 0, $result = 0;
 var $vararg_buffer = 0, label = 0, sp = 0;
 sp = STACKTOP;
 STACKTOP = STACKTOP + 32|0; if ((STACKTOP|0) >= (STACK_MAX|0)) abort();
 $vararg_buffer = sp;
 $1 = $screen;
 $2 = $fileName;
 $3 = $2;
 $4 = (_IMG_Load(($3|0))|0);
 $image = $4;
 $5 = $image;
 $6 = ($5|0)!=(0|0);
 if (!($6)) {
  $7 = (_SDL_GetError()|0);
  HEAP32[$vararg_buffer>>2] = $7;
  (_printf((8|0),($vararg_buffer|0))|0);
  $0 = 0;
  $37 = $0;
  STACKTOP = sp;return ($37|0);
 }
 $8 = $image;
 $9 = (($8) + 4|0);
 $10 = HEAP32[$9>>2]|0;
 $11 = (($10) + 8|0);
 $12 = HEAP8[$11>>0]|0;
 $13 = $12&255;
 $14 = ($13|0)==(32);
 if (!($14)) {
  ___assert_fail((24|0),(64|0),15,(88|0));
  // unreachable;
 }
 $15 = $image;
 $16 = (($15) + 4|0);
 $17 = HEAP32[$16>>2]|0;
 $18 = (($17) + 9|0);
 $19 = HEAP8[$18>>0]|0;
 $20 = $19&255;
 $21 = ($20|0)==(4);
 if (!($21)) {
  ___assert_fail((104|0),(64|0),16,(88|0));
  // unreachable;
 }
 $22 = $image;
 $23 = (($22) + 16|0);
 $24 = HEAP32[$23>>2]|0;
 $25 = $image;
 $26 = (($25) + 8|0);
 $27 = HEAP32[$26>>2]|0;
 $28 = $27<<2;
 $29 = ($24|0)==($28|0);
 if (!($29)) {
  ___assert_fail((144|0),(64|0),17,(88|0));
  // unreachable;
 }
 $30 = $image;
 $31 = (($30) + 8|0);
 $32 = HEAP32[$31>>2]|0;
 $result = $32;
 $33 = $image;
 $34 = $1;
 (_SDL_UpperBlit(($33|0),(0|0),($34|0),(0|0))|0);
 $35 = $image;
 _SDL_FreeSurface(($35|0));
 $36 = $result;
 $0 = $36;
 $37 = $0;
 STACKTOP = sp;return ($37|0);
}
function _main() {
 var $0 = 0, $1 = 0, $2 = 0, $3 = 0, $4 = 0, $5 = 0, $6 = 0, $7 = 0, $8 = 0, $result = 0, $screen = 0, $vararg_buffer = 0, label = 0, sp = 0;
 sp = STACKTOP;
 STACKTOP = STACKTOP + 16|0; if ((STACKTOP|0) >= (STACK_MAX|0)) abort();
 $vararg_buffer = sp;
 $0 = 0;
 (_SDL_Init(32)|0);
 $1 = (_SDL_SetVideoMode(600,450,32,0)|0);
 $screen = $1;
 $result = 0;
 $2 = $screen;
 $3 = (_testImage($2,176)|0);
 $4 = $result;
 $5 = $4 | $3;
 $result = $5;
 $6 = $result;
 $7 = ($6|0)!=(0);
 if ($7) {
  $8 = $screen;
  (_SDL_Flip(($8|0))|0);
  (_printf((216|0),($vararg_buffer|0))|0);
  _SDL_Quit();
  STACKTOP = sp;return 0;
 } else {
  ___assert_fail((192|0),(64|0),33,(208|0));
  // unreachable;
 }
 return (0)|0;
}