source: libpipi/trunk/pipi/codec/gdi.c @ 2909

Last change on this file since 2909 was 2909, checked in by Sam Hocevar, 12 years ago

libpipi: fix a sign bug in the GDI loader.

File size: 4.1 KB
Line 
1/*
2 *  libpipi       Pathetic image processing interface library
3 *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
4 *                All Rights Reserved
5 *
6 *  $Id$
7 *
8 *  This library is free software. It comes without any warranty, to
9 *  the extent permitted by applicable law. You can redistribute it
10 *  and/or modify it under the terms of the Do What The Fuck You Want
11 *  To Public License, Version 2, as published by Sam Hocevar. See
12 *  http://sam.zoy.org/wtfpl/COPYING for more details.
13 */
14
15/*
16 * gdi.c: Windows GDI I/O functions (BMP only)
17 */
18
19#include "config.h"
20
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24
25#include <windows.h>
26
27#include "pipi.h"
28#include "pipi_internals.h"
29
30pipi_image_t *pipi_load_gdi(const char *name)
31{
32    BITMAPINFO binfo;
33    pipi_image_t *img;
34    pipi_pixels_t *p;
35    uint8_t *data;
36    HBITMAP hbmap;
37    HDC hdc;
38    int x, y;
39
40    hbmap = (HBITMAP)LoadImage(NULL, name, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
41    if(!hbmap)
42        return NULL;
43
44    hdc = CreateCompatibleDC(NULL);
45    SelectObject(hdc, hbmap);
46
47    memset(&binfo, 0, sizeof(binfo));
48    binfo.bmiHeader.biSize = sizeof(binfo.bmiHeader);
49    if(!GetDIBits(hdc, hbmap, 0, 0, 0, &binfo, DIB_RGB_COLORS))
50    {
51        ReleaseDC(0, hdc);
52        DeleteObject(hbmap);
53        return NULL;
54    }
55
56    img = pipi_new(binfo.bmiHeader.biWidth, binfo.bmiHeader.biHeight);
57    p = pipi_getpixels(img, PIPI_PIXELS_RGBA_C);
58    data = p->pixels;
59
60    binfo.bmiHeader.biBitCount = 32;
61    binfo.bmiHeader.biCompression = BI_RGB;
62    binfo.bmiHeader.biHeight = - abs(binfo.bmiHeader.biHeight);
63    if(!GetDIBits(hdc, hbmap, 0, abs(binfo.bmiHeader.biHeight), data,
64                  &binfo, DIB_RGB_COLORS))
65    {
66        ReleaseDC(0, hdc);
67        DeleteObject(hbmap);
68        return NULL;
69    }
70
71    /* FIXME: get rid of this loop, maybe by using BITMAPV4HEADER above
72     * so that GDI reorders the pixels for us. */
73    for(y = 0; y < img->h; y++)
74        for(x = 0; x < img->w; x++)
75        {
76            /* Swap B and R, don't touch G and A. */
77            uint8_t tmp = data[0]; data[0] = data[2]; data[2] = tmp;
78            data += 4;
79        }
80
81    img->codec_priv = NULL;
82
83    img->wrap = 0;
84    img->u8 = 1;
85
86    ReleaseDC(0, hdc);
87    DeleteObject(hbmap);
88
89    return img;
90}
91
92int pipi_save_gdi(pipi_image_t *img, const char *name)
93{
94    BITMAPINFOHEADER binfo;
95    BITMAPFILEHEADER bfheader;
96    uint8_t dummy[4] = { 0 };
97    HANDLE hfile;
98    pipi_pixels_t *p;
99    DWORD ret = 0;
100    uint8_t *data;
101    int x, y, padding;
102
103    p = pipi_getpixels(img, PIPI_PIXELS_RGBA_C);
104    data = p->pixels;
105
106    padding = ((img->w * 3) + 3) / 4 * 4 - img->w * 3;
107
108    memset(&binfo, 0, sizeof(binfo));
109    binfo.biSize = sizeof(binfo);
110    binfo.biWidth = img->w;
111    binfo.biHeight = img->h;
112    binfo.biPlanes = 1;
113    binfo.biBitCount = 24;
114    binfo.biCompression = BI_RGB;
115    binfo.biSizeImage = (img->w * 3 + padding) * img->h;
116
117    memset(&bfheader, 0, sizeof(bfheader));
118    bfheader.bfType = 0x4D42;
119    bfheader.bfOffBits = sizeof(bfheader) + sizeof(binfo);
120    bfheader.bfSize = bfheader.bfOffBits + binfo.biSizeImage;
121
122    /* We don’t even create the bitmap object, since we know exactly
123     * what kind of file we are saving. But later, when we support
124     * different depths and BMP options, we'll need to care about it. */
125    hfile = CreateFile(name, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
126                       FILE_ATTRIBUTE_ARCHIVE, NULL);
127    if(!hfile)
128        return -1;
129    WriteFile(hfile, &bfheader, sizeof(bfheader), &ret, NULL);
130    WriteFile(hfile, &binfo, sizeof(binfo), &ret, NULL);
131    for(y = 0; y < img->h; y++)
132    {
133        for(x = 0; x < img->w; x++)
134        {
135            uint8_t tmp[3];
136            tmp[0] = data[4 * (img->w * (img->h - 1 - y) + x) + 2];
137            tmp[1] = data[4 * (img->w * (img->h - 1 - y) + x) + 1];
138            tmp[2] = data[4 * (img->w * (img->h - 1 - y) + x) + 0];
139            WriteFile(hfile, tmp, 3, &ret, NULL);
140        }
141        if(padding)
142            WriteFile(hfile, dummy, padding, &ret, NULL);
143    }
144    CloseHandle(hfile);
145
146    return 0;
147}
148
149/*
150 * XXX: The following functions are local.
151 */
152
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