mpng.c

multi-tabed terminal based on rxvt

/*--------------------------------*-C-*---------------------------------*
 * File:    mpng.c
 *----------------------------------------------------------------------*
 *
 * All portions of code are copyright by their respective author/s.
 * Copyright (c) 1999-2002   Toshikaz Hirabayashi
 * Copyright (c) 2004        Jingmin Zhou <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *----------------------------------------------------------------------*/

#include "../config.h"
#include "rxvt.h"


#ifdef USE_PNG

static void
png_cexcept_error (png_structp png_ptr, png_const_charp msg)
{
    if(png_ptr){
	rxvt_msg (DBG_ERROR, DBG_IMAGES, "png file read error: %s\n", msg);
    }
}


long
PngReadFileToPixmap (Display* display, Window window, GC gc, char* filename, Pixmap* pixmap, long* w, long* h)
{
    int red_mask, green_mask, blue_mask;
    int red_shift, green_shift, blue_shift;
    int start_shift, msb_flag;
    unsigned int start_mask, udat;
    XWindowAttributes win_attr;
    FILE* ifile;
  long display_depth;
      png_byte            sig[8];
  png_infop info_ptr;
  png_structp png_ptr;
      png_uint_32 png_width;
    png_uint_32 png_height;
    int png_depth;
    int png_color_type;
png_uint_32 png_row_bytes;
  png_uint_32 png_channels;
    long rwidth;
    long rheight;
    long components;
    unsigned char* buf;
    png_byte** png_row_ptrs;
    long vwidth;
    long vheight;
    long stretched;
    XImage* image;
    Visual* visual;
    Pixmap pix;
    int i;
    char* data1;
    unsigned char r,g,b;
    long ptr = 0;
    long ptr2 = 0;
    long j;

    red_mask = green_mask = blue_mask = 0;
    red_shift = green_shift = blue_shift = 0;

    ifile = fopen(filename,"r");
    if (ifile == NULL){
      return -1;
    }
    display_depth = XDefaultDepth(display,XDefaultScreen(display));

    fread(sig, 1, 8, ifile);
    if (!png_check_sig(sig, 8)){
      fclose(ifile);
      return -1;
    }
    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
    if (png_ptr == NULL){
      fclose(ifile);
      return -1;
    } 
    info_ptr = png_create_info_struct(png_ptr);
    if (info_ptr == NULL){
      png_destroy_read_struct(&png_ptr, NULL, NULL);
      fclose(ifile);
      return -1;
    }

    png_init_io(png_ptr, ifile);
    png_set_sig_bytes(png_ptr, 8);
    png_read_info(png_ptr, info_ptr);
    png_get_IHDR(png_ptr, info_ptr, &png_width, &png_height, &png_depth,
            &png_color_type, NULL, NULL, NULL);
    if (png_depth == 16){
      png_set_strip_16(png_ptr);
    }
    png_row_bytes = png_get_rowbytes(png_ptr, info_ptr);
    png_channels = png_get_channels(png_ptr, info_ptr);

    if (png_depth < 8){
      if (png_color_type == PNG_COLOR_TYPE_GRAY ){
        png_set_gray_1_2_4_to_8(png_ptr);
        png_row_bytes = png_width;
      }else{
        png_set_expand(png_ptr);
        png_row_bytes = png_width;
        png_row_bytes = png_width * 3;
        png_channels = 3;
      }
    }
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)){
      png_set_expand(png_ptr);
      png_row_bytes = png_width;
    }
    if (png_color_type == PNG_COLOR_TYPE_GRAY ||
        png_color_type == PNG_COLOR_TYPE_GRAY_ALPHA){
      png_set_gray_to_rgb(png_ptr);
      png_row_bytes = png_width;
    }

    if (png_color_type == PNG_COLOR_TYPE_PALETTE){
      png_set_palette_to_rgb(png_ptr);
      png_row_bytes = png_width * 3;
      png_channels = 3;
    }

    rwidth = png_width;
    rheight = png_height;
    components = png_channels;

    /* possible integer overflow? */
    assert ((int) png_row_bytes > 0);
    assert ((int) png_height > 0);
    assert (((int)png_row_bytes) * ((int)png_height) * sizeof(png_byte) > 0);
    buf = rxvt_malloc(png_row_bytes * png_height * sizeof(png_byte));
    if (buf == NULL){
      rxvt_msg (DBG_ERROR, DBG_IMAGES, "png read error: out of memory..\n");
      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
      fclose(ifile);
      return -1;
    }
    /* possible integer overflow? */
    assert ((int) png_height > 0);
    assert (sizeof(png_bytep) * ((int)png_height) > 0);
    png_row_ptrs = rxvt_malloc (sizeof(png_bytep)*png_height);
    if (png_row_ptrs == NULL){
      rxvt_msg (DBG_ERROR, DBG_IMAGES, "png read error: out of memory..\n");
      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
      fclose(ifile);
      return -1;
    }

    for(i = 0; i < (int)png_height; i++){
      png_row_ptrs[i] = (png_byte*)(buf + i * png_row_bytes);
    }
    png_read_image(png_ptr, png_row_ptrs);
    png_read_end(png_ptr,NULL);
    rxvt_free(png_row_ptrs);

    vwidth = *w;
    vheight = *h;
    stretched =0;
    if (*w == 0 || *h == 0){
      *w = rwidth;
      *h = rheight;
    }else{
      if ((long)((double)rwidth * vheight/vwidth) < rheight){
        *w = (long)((double)vheight * rwidth/rheight);
      }else{
        *h = (long)((double)vwidth * rheight/rwidth);
      }
      stretched = 1;
    }
    vwidth = *w;
    vheight = *h;



    image = 0;
    visual = XDefaultVisual(display,XDefaultScreen(display));
    if (display_depth >16){
      image = XCreateImage(display,visual, display_depth,
                           ZPixmap,0,0,vwidth,vheight,32,0);
    }else
    if (display_depth >8){
      image = XCreateImage(display,visual, display_depth,
                           ZPixmap,0,0,vwidth,vheight,16,0);
    }else{
      image = XCreateImage(display,visual, display_depth,
                           ZPixmap,0,0,vwidth,vheight,8,0);
    }

    msb_flag = (ImageByteOrder(display) == MSBFirst)?1:0;

    if (XGetWindowAttributes(display,
                     RootWindow(display, DefaultScreen(display)),
                     &win_attr) == 0) {
        fclose(ifile);
                 return -1;
    }

    if ((win_attr.depth == 24) || (win_attr.depth == 16)) {
      unsigned int n;
      if (win_attr.depth == 24) {
        start_shift = 24;
        start_mask = 0x80000000;
      }else{
        start_shift = 8;
        start_mask = 0x8000;
      }
      red_mask = win_attr.visual->red_mask;
      red_shift = start_shift;
      n = start_mask;
      while (!(n & red_mask)) {
        n >>= 1;
        red_shift--;
      }
      green_mask = win_attr.visual->green_mask;
      green_shift = start_shift;
      n = start_mask;
      while (!(n & green_mask)) {
        n >>= 1;
        green_shift--;
      }
      blue_mask = win_attr.visual->blue_mask;
      blue_shift = start_shift;
      n = start_mask;
      while (!(n & blue_mask)) {
        n >>= 1;
        blue_shift--;
      }
    }

    /* possible integer overflow? */
    assert ((int) image->bytes_per_line > 0);
    assert ((int) vheight > 0);
    assert (((int)image->bytes_per_line) * ((int)vheight) > 0);
    data1 = rxvt_malloc(image->bytes_per_line * vheight);
    if (image->bits_per_pixel ==32){
      if (components == 3 || components == 4){
        for(i=0; i<vheight; i++){
          for(j=0; j<vwidth; j++){
            if (stretched != 0){
              ptr = (long)((double)i*rheight/vheight)*rwidth
                   + (long)((double)j*rwidth/vwidth);
              ptr *= 3;
            }
            r = buf[ptr++];
            g = buf[ptr++];
            b = buf[ptr++];
            if (components == 4){
              ptr++;
            }
            udat = 0;
            if (red_shift >= 0){
              udat |= (((int)r << red_shift) & red_mask);
            }else{
              udat |= (((int)r >> (-red_shift)) & red_mask);
            }
            if (green_shift >= 0){
              udat |= (((int)g << green_shift) & green_mask);
            }else{
              udat |= (((int)g >> (-green_shift)) & green_mask);
            }
            if (blue_shift >= 0){
              udat |= (((int)b << blue_shift) & blue_mask);
            }else{
              udat |= (((int)b >> (-blue_shift)) & blue_mask);
            }
            if (msb_flag){
              ((unsigned char*)data1)[ptr2++] = (udat & 0xff000000)>>24;
              ((unsigned char*)data1)[ptr2++] = (udat & 0xff0000)>>16;
              ((unsigned char*)data1)[ptr2++] = (udat & 0xff00)>>8;