rpng-win.c
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- /*---------------------------------------------------------------------------
- rpng - simple PNG display program rpng-win.c
- This program decodes and displays PNG images, with gamma correction and
- optionally with a user-specified background color (in case the image has
- transparency). It is very nearly the most basic PNG viewer possible.
- This version is for 32-bit Windows; it may compile under 16-bit Windows
- with a little tweaking (or maybe not).
- to do:
- - handle quoted command-line args (especially filenames with spaces)
- - have minimum window width: oh well
- - use %.1023s to simplify truncation of title-bar string?
- ---------------------------------------------------------------------------
- Changelog:
- - 1.00: initial public release
- - 1.01: modified to allow abbreviated options; fixed long/ulong mis-
- match; switched to png_jmpbuf() macro
- - 1.02: added extra set of parentheses to png_jmpbuf() macro; fixed
- command-line parsing bug
- - 1.10: enabled "message window"/console (thanks to David Geldreich)
- - 2.00: dual-licensed (added GNU GPL)
- - 2.01: fixed improper display of usage screen on PNG error(s)
- ---------------------------------------------------------------------------
- Copyright (c) 1998-2008 Greg Roelofs. All rights reserved.
- This software is provided "as is," without warranty of any kind,
- express or implied. In no event shall the author or contributors
- be held liable for any damages arising in any way from the use of
- this software.
- The contents of this file are DUAL-LICENSED. You may modify and/or
- redistribute this software according to the terms of one of the
- following two licenses (at your option):
- LICENSE 1 ("BSD-like with advertising clause"):
- Permission is granted to anyone to use this software for any purpose,
- including commercial applications, and to alter it and redistribute
- it freely, subject to the following restrictions:
- 1. Redistributions of source code must retain the above copyright
- notice, disclaimer, and this list of conditions.
- 2. Redistributions in binary form must reproduce the above copyright
- notice, disclaimer, and this list of conditions in the documenta-
- tion and/or other materials provided with the distribution.
- 3. All advertising materials mentioning features or use of this
- software must display the following acknowledgment:
- This product includes software developed by Greg Roelofs
- and contributors for the book, "PNG: The Definitive Guide,"
- published by O'Reilly and Associates.
- LICENSE 2 (GNU GPL v2 or later):
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- ---------------------------------------------------------------------------*/
- #define PROGNAME "rpng-win"
- #define LONGNAME "Simple PNG Viewer for Windows"
- #define VERSION "2.01 of 16 March 2008"
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <time.h>
- #include <windows.h>
- #include <conio.h> /* only for _getch() */
- /* #define DEBUG : this enables the Trace() macros */
- #include "readpng.h" /* typedefs, common macros, readpng prototypes */
- /* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
- #define alpha_composite(composite, fg, alpha, bg) {
- ush temp = ((ush)(fg)*(ush)(alpha) +
- (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);
- (composite) = (uch)((temp + (temp >> 8)) >> 8);
- }
- /* local prototypes */
- static int rpng_win_create_window(HINSTANCE hInst, int showmode);
- static int rpng_win_display_image(void);
- static void rpng_win_cleanup(void);
- LRESULT CALLBACK rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
- static char titlebar[1024];
- static char *progname = PROGNAME;
- static char *appname = LONGNAME;
- static char *filename;
- static FILE *infile;
- static char *bgstr;
- static uch bg_red=0, bg_green=0, bg_blue=0;
- static double display_exponent;
- static ulg image_width, image_height, image_rowbytes;
- static int image_channels;
- static uch *image_data;
- /* Windows-specific variables */
- static ulg wimage_rowbytes;
- static uch *dib;
- static uch *wimage_data;
- static BITMAPINFOHEADER *bmih;
- static HWND global_hwnd;
- int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
- {
- char *args[1024]; /* arbitrary limit, but should suffice */
- char *p, *q, **argv = args;
- int argc = 0;
- int rc, alen, flen;
- int error = 0;
- int have_bg = FALSE;
- double LUT_exponent; /* just the lookup table */
- double CRT_exponent = 2.2; /* just the monitor */
- double default_display_exponent; /* whole display system */
- MSG msg;
- filename = (char *)NULL;
- /* First reenable console output, which normally goes to the bit bucket
- * for windowed apps. Closing the console window will terminate the
- * app. Thanks to David.Geldreich@realviz.com for supplying the magical
- * incantation. */
- AllocConsole();
- freopen("CONOUT$", "a", stderr);
- freopen("CONOUT$", "a", stdout);
- /* Next set the default value for our display-system exponent, i.e.,
- * the product of the CRT exponent and the exponent corresponding to
- * the frame-buffer's lookup table (LUT), if any. This is not an
- * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
- * ones), but it should cover 99% of the current possibilities. And
- * yes, these ifdefs are completely wasted in a Windows program... */
- #if defined(NeXT)
- LUT_exponent = 1.0 / 2.2;
- /*
- if (some_next_function_that_returns_gamma(&next_gamma))
- LUT_exponent = 1.0 / next_gamma;
- */
- #elif defined(sgi)
- LUT_exponent = 1.0 / 1.7;
- /* there doesn't seem to be any documented function to get the
- * "gamma" value, so we do it the hard way */
- infile = fopen("/etc/config/system.glGammaVal", "r");
- if (infile) {
- double sgi_gamma;
- fgets(tmpline, 80, infile);
- fclose(infile);
- sgi_gamma = atof(tmpline);
- if (sgi_gamma > 0.0)
- LUT_exponent = 1.0 / sgi_gamma;
- }
- #elif defined(Macintosh)
- LUT_exponent = 1.8 / 2.61;
- /*
- if (some_mac_function_that_returns_gamma(&mac_gamma))
- LUT_exponent = mac_gamma / 2.61;
- */
- #else
- LUT_exponent = 1.0; /* assume no LUT: most PCs */
- #endif
- /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
- default_display_exponent = LUT_exponent * CRT_exponent;
- /* If the user has set the SCREEN_GAMMA environment variable as suggested
- * (somewhat imprecisely) in the libpng documentation, use that; otherwise
- * use the default value we just calculated. Either way, the user may
- * override this via a command-line option. */
- if ((p = getenv("SCREEN_GAMMA")) != NULL)
- display_exponent = atof(p);
- else
- display_exponent = default_display_exponent;
- /* Windows really hates command lines, so we have to set up our own argv.
- * Note that we do NOT bother with quoted arguments here, so don't use
- * filenames with spaces in 'em! */
- argv[argc++] = PROGNAME;
- p = cmd;
- for (;;) {
- if (*p == ' ')
- while (*++p == ' ')
- ;
- /* now p points at the first non-space after some spaces */
- if (*p == ' ')
- break; /* nothing after the spaces: done */
- argv[argc++] = q = p;
- while (*q && *q != ' ')
- ++q;
- /* now q points at a space or the end of the string */
- if (*q == ' ')
- break; /* last argv already terminated; quit */
- *q = ' '; /* change space to terminator */
- p = q + 1;
- }
- argv[argc] = NULL; /* terminate the argv array itself */
- /* Now parse the command line for options and the PNG filename. */
- while (*++argv && !error) {
- if (!strncmp(*argv, "-gamma", 2)) {
- if (!*++argv)
- ++error;
- else {
- display_exponent = atof(*argv);
- if (display_exponent <= 0.0)
- ++error;
- }
- } else if (!strncmp(*argv, "-bgcolor", 2)) {
- if (!*++argv)
- ++error;
- else {
- bgstr = *argv;
- if (strlen(bgstr) != 7 || bgstr[0] != '#')
- ++error;
- else
- have_bg = TRUE;
- }
- } else {
- if (**argv != '-') {
- filename = *argv;
- if (argv[1]) /* shouldn't be any more args after filename */
- ++error;
- } else
- ++error; /* not expecting any other options */
- }
- }
- if (!filename)
- ++error;
- /* print usage screen if any errors up to this point */
- if (error) {
- int ch;
- fprintf(stderr, "n%s %s: %snn", PROGNAME, VERSION, appname);
- readpng_version_info();
- fprintf(stderr, "n"
- "Usage: %s [-gamma exp] [-bgcolor bg] file.pngn"
- " exp ttransfer-function exponent (``gamma'') of the displayn"
- "tt system in floating-point format (e.g., ``%.1f''); equaln"
- "tt to the product of the lookup-table exponent (varies)n"
- "tt and the CRT exponent (usually 2.2); must be positiven"
- " bg tdesired background color in 7-character hex RGB formatn"
- "tt (e.g., ``#ff7700'' for orange: same as HTML colors);n"
- "tt used with transparent imagesn"
- "nPress Q, Esc or mouse button 1 after image is displayed to quit.n"
- "Press Q or Esc to quit this usage screen.n"
- "n", PROGNAME, default_display_exponent);
- do
- ch = _getch();
- while (ch != 'q' && ch != 'Q' && ch != 0x1B);
- exit(1);
- }
- if (!(infile = fopen(filename, "rb"))) {
- fprintf(stderr, PROGNAME ": can't open PNG file [%s]n", filename);
- ++error;
- } else {
- if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
- switch (rc) {
- case 1:
- fprintf(stderr, PROGNAME
- ": [%s] is not a PNG file: incorrect signaturen",
- filename);
- break;
- case 2:
- fprintf(stderr, PROGNAME
- ": [%s] has bad IHDR (libpng longjmp)n", filename);
- break;
- case 4:
- fprintf(stderr, PROGNAME ": insufficient memoryn");
- break;
- default:
- fprintf(stderr, PROGNAME
- ": unknown readpng_init() errorn");
- break;
- }
- ++error;
- }
- if (error)
- fclose(infile);
- }
- if (error) {
- int ch;
- fprintf(stderr, PROGNAME ": aborting.n");
- do
- ch = _getch();
- while (ch != 'q' && ch != 'Q' && ch != 0x1B);
- exit(2);
- } else {
- fprintf(stderr, "n%s %s: %sn", PROGNAME, VERSION, appname);
- fprintf(stderr,
- "n [console window: closing this window will terminate %s]nn",
- PROGNAME);
- }
- /* set the title-bar string, but make sure buffer doesn't overflow */
- alen = strlen(appname);
- flen = strlen(filename);
- if (alen + flen + 3 > 1023)
- sprintf(titlebar, "%s: ...%s", appname, filename+(alen+flen+6-1023));
- else
- sprintf(titlebar, "%s: %s", appname, filename);
- /* if the user didn't specify a background color on the command line,
- * check for one in the PNG file--if not, the initialized values of 0
- * (black) will be used */
- if (have_bg) {
- unsigned r, g, b; /* this approach quiets compiler warnings */
- sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
- bg_red = (uch)r;
- bg_green = (uch)g;
- bg_blue = (uch)b;
- } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
- readpng_cleanup(TRUE);
- fprintf(stderr, PROGNAME
- ": libpng error while checking for background colorn");
- exit(2);
- }
- /* do the basic Windows initialization stuff, make the window and fill it
- * with the background color */
- if (rpng_win_create_window(hInst, showmode))
- exit(2);
- /* decode the image, all at once */
- Trace((stderr, "calling readpng_get_image()n"))
- image_data = readpng_get_image(display_exponent, &image_channels,
- &image_rowbytes);
- Trace((stderr, "done with readpng_get_image()n"))
- /* done with PNG file, so clean up to minimize memory usage (but do NOT
- * nuke image_data!) */
- readpng_cleanup(FALSE);
- fclose(infile);
- if (!image_data) {
- fprintf(stderr, PROGNAME ": unable to decode PNG imagen");
- exit(3);
- }
- /* display image (composite with background if requested) */
- Trace((stderr, "calling rpng_win_display_image()n"))
- if (rpng_win_display_image()) {
- free(image_data);
- exit(4);
- }
- Trace((stderr, "done with rpng_win_display_image()n"))
- /* wait for the user to tell us when to quit */
- printf(
- "Done. Press Q, Esc or mouse button 1 (within image window) to quit.n");
- fflush(stdout);
- while (GetMessage(&msg, NULL, 0, 0)) {
- TranslateMessage(&msg);
- DispatchMessage(&msg);
- }
- /* OK, we're done: clean up all image and Windows resources and go away */
- rpng_win_cleanup();
- return msg.wParam;
- }
- static int rpng_win_create_window(HINSTANCE hInst, int showmode)
- {
- uch *dest;
- int extra_width, extra_height;
- ulg i, j;
- WNDCLASSEX wndclass;
- /*---------------------------------------------------------------------------
- Allocate memory for the display-specific version of the image (round up
- to multiple of 4 for Windows DIB).
- ---------------------------------------------------------------------------*/
- wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
- if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
- wimage_rowbytes*image_height)))
- {
- return 4; /* fail */
- }
- /*---------------------------------------------------------------------------
- Initialize the DIB. Negative height means to use top-down BMP ordering
- (must be uncompressed, but that's what we want). Bit count of 1, 4 or 8
- implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
- directly => wimage_data begins immediately after BMP header.
- ---------------------------------------------------------------------------*/
- memset(dib, 0, sizeof(BITMAPINFOHEADER));
- bmih = (BITMAPINFOHEADER *)dib;
- bmih->biSize = sizeof(BITMAPINFOHEADER);
- bmih->biWidth = image_width;
- bmih->biHeight = -((long)image_height);
- bmih->biPlanes = 1;
- bmih->biBitCount = 24;
- bmih->biCompression = 0;
- wimage_data = dib + sizeof(BITMAPINFOHEADER);
- /*---------------------------------------------------------------------------
- Fill in background color (black by default); data are in BGR order.
- ---------------------------------------------------------------------------*/
- for (j = 0; j < image_height; ++j) {
- dest = wimage_data + j*wimage_rowbytes;
- for (i = image_width; i > 0; --i) {
- *dest++ = bg_blue;
- *dest++ = bg_green;
- *dest++ = bg_red;
- }
- }
- /*---------------------------------------------------------------------------
- Set the window parameters.
- ---------------------------------------------------------------------------*/
- memset(&wndclass, 0, sizeof(wndclass));
- wndclass.cbSize = sizeof(wndclass);
- wndclass.style = CS_HREDRAW | CS_VREDRAW;
- wndclass.lpfnWndProc = rpng_win_wndproc;
- wndclass.hInstance = hInst;
- wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
- wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
- wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
- wndclass.lpszMenuName = NULL;
- wndclass.lpszClassName = progname;
- wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
- RegisterClassEx(&wndclass);
- /*---------------------------------------------------------------------------
- Finally, create the window.
- ---------------------------------------------------------------------------*/
- extra_width = 2*(GetSystemMetrics(SM_CXBORDER) +
- GetSystemMetrics(SM_CXDLGFRAME));
- extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
- GetSystemMetrics(SM_CYDLGFRAME)) +
- GetSystemMetrics(SM_CYCAPTION);
- global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
- CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
- image_height+extra_height, NULL, NULL, hInst, NULL);
- ShowWindow(global_hwnd, showmode);
- UpdateWindow(global_hwnd);
- return 0;
- } /* end function rpng_win_create_window() */
- static int rpng_win_display_image()
- {
- uch *src, *dest;
- uch r, g, b, a;
- ulg i, row, lastrow;
- RECT rect;
- Trace((stderr, "beginning display loop (image_channels == %d)n",
- image_channels))
- Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)n",
- image_width, image_rowbytes, wimage_rowbytes))
- /*---------------------------------------------------------------------------
- Blast image data to buffer. This whole routine takes place before the
- message loop begins, so there's no real point in any pseudo-progressive
- display...
- ---------------------------------------------------------------------------*/
- for (lastrow = row = 0; row < image_height; ++row) {
- src = image_data + row*image_rowbytes;
- dest = wimage_data + row*wimage_rowbytes;
- if (image_channels == 3) {
- for (i = image_width; i > 0; --i) {
- r = *src++;
- g = *src++;
- b = *src++;
- *dest++ = b;
- *dest++ = g; /* note reverse order */
- *dest++ = r;
- }
- } else /* if (image_channels == 4) */ {
- for (i = image_width; i > 0; --i) {
- r = *src++;
- g = *src++;
- b = *src++;
- a = *src++;
- if (a == 255) {
- *dest++ = b;
- *dest++ = g;
- *dest++ = r;
- } else if (a == 0) {
- *dest++ = bg_blue;
- *dest++ = bg_green;
- *dest++ = bg_red;
- } else {
- /* this macro (copied from png.h) composites the
- * foreground and background values and puts the
- * result into the first argument; there are no
- * side effects with the first argument */
- alpha_composite(*dest++, b, a, bg_blue);
- alpha_composite(*dest++, g, a, bg_green);
- alpha_composite(*dest++, r, a, bg_red);
- }
- }
- }
- /* display after every 16 lines */
- if (((row+1) & 0xf) == 0) {
- rect.left = 0L;
- rect.top = (LONG)lastrow;
- rect.right = (LONG)image_width; /* possibly off by one? */
- rect.bottom = (LONG)lastrow + 16L; /* possibly off by one? */
- InvalidateRect(global_hwnd, &rect, FALSE);
- UpdateWindow(global_hwnd); /* similar to XFlush() */
- lastrow = row + 1;
- }
- }
- Trace((stderr, "calling final image-flush routinen"))
- if (lastrow < image_height) {
- rect.left = 0L;
- rect.top = (LONG)lastrow;
- rect.right = (LONG)image_width; /* possibly off by one? */
- rect.bottom = (LONG)image_height; /* possibly off by one? */
- InvalidateRect(global_hwnd, &rect, FALSE);
- UpdateWindow(global_hwnd); /* similar to XFlush() */
- }
- /*
- last param determines whether or not background is wiped before paint
- InvalidateRect(global_hwnd, NULL, TRUE);
- UpdateWindow(global_hwnd);
- */
- return 0;
- }
- static void rpng_win_cleanup()
- {
- if (image_data) {
- free(image_data);
- image_data = NULL;
- }
- if (dib) {
- free(dib);
- dib = NULL;
- }
- }
- LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
- {
- HDC hdc;
- PAINTSTRUCT ps;
- int rc;
- switch (iMsg) {
- case WM_CREATE:
- /* one-time processing here, if any */
- return 0;
- case WM_PAINT:
- hdc = BeginPaint(hwnd, &ps);
- /* dest */
- rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
- /* source */
- 0, 0, image_width, image_height,
- wimage_data, (BITMAPINFO *)bmih,
- /* iUsage: no clue */
- 0, SRCCOPY);
- EndPaint(hwnd, &ps);
- return 0;
- /* wait for the user to tell us when to quit */
- case WM_CHAR:
- switch (wP) { /* only need one, so ignore repeat count */
- case 'q':
- case 'Q':
- case 0x1B: /* Esc key */
- PostQuitMessage(0);
- }
- return 0;
- case WM_LBUTTONDOWN: /* another way of quitting */
- case WM_DESTROY:
- PostQuitMessage(0);
- return 0;
- }
- return DefWindowProc(hwnd, iMsg, wP, lP);
- }