fl_read_image.cxx
来自「SRI international 发布的OAA框架软件」· CXX 代码 · 共 398 行
CXX
398 行
//
// "$Id: fl_read_image.cxx,v 1.1.1.1 2003/06/03 22:25:46 agno Exp $"
//
// X11 image reading routines for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2003 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems to "fltk-bugs@fltk.org".
//
#include <FL/x.H>
#include <FL/fl_draw.H>
#include "flstring.h"
#ifdef DEBUG
# include <stdio.h>
#endif // DEBUG
#ifdef WIN32
# include "fl_read_image_win32.cxx"
#elif defined(__APPLE__)
# include "fl_read_image_mac.cxx"
#else
# include <X11/Xutil.h>
# ifdef __sgi
# include <X11/extensions/readdisplay.h>
# endif // __sgi
//
// 'fl_read_image()' - Read an image from the current window.
//
uchar * // O - Pixel buffer or NULL if failed
fl_read_image(uchar *p, // I - Pixel buffer or NULL to allocate
int X, // I - Left position
int Y, // I - Top position
int w, // I - Width of area to read
int h, // I - Height of area to read
int alpha) { // I - Alpha value for image (0 for none)
XImage *image; // Captured image
int i, maxindex; // Looping vars
int x, y; // Current X & Y in image
int d; // Depth of image
unsigned char *line, // Array to hold image row
*line_ptr; // Pointer to current line image
unsigned char *pixel; // Current color value
XColor colors[4096]; // Colors from the colormap...
unsigned char cvals[4096][3]; // Color values from the colormap...
unsigned index_mask,
index_shift,
red_mask,
red_shift,
green_mask,
green_shift,
blue_mask,
blue_shift;
//
// Under X11 we have the option of the XGetImage() interface or SGI's
// ReadDisplay extension which does all of the really hard work for
// us...
//
# ifdef __sgi
if (XReadDisplayQueryExtension(fl_display, &i, &i)) {
image = XReadDisplay(fl_display, fl_window, X, Y, w, h, 0, NULL);
} else
# else
image = 0;
# endif // __sgi
if (!image) {
image = XGetImage(fl_display, fl_window, X, Y, w, h, AllPlanes, ZPixmap);
}
if (!image) return 0;
#ifdef DEBUG
printf("width = %d\n", image->width);
printf("height = %d\n", image->height);
printf("xoffset = %d\n", image->xoffset);
printf("format = %d\n", image->format);
printf("data = %p\n", image->data);
printf("byte_order = %d\n", image->byte_order);
printf("bitmap_unit = %d\n", image->bitmap_unit);
printf("bitmap_bit_order = %d\n", image->bitmap_bit_order);
printf("bitmap_pad = %d\n", image->bitmap_pad);
printf("depth = %d\n", image->depth);
printf("bytes_per_line = %d\n", image->bytes_per_line);
printf("bits_per_pixel = %d\n", image->bits_per_pixel);
printf("red_mask = %08x\n", image->red_mask);
printf("green_mask = %08x\n", image->green_mask);
printf("blue_mask = %08x\n", image->blue_mask);
#endif // DEBUG
d = alpha ? 4 : 3;
// Allocate the image data array as needed...
if (!p) p = new uchar[w * h * d];
// Initialize the default colors/alpha in the whole image...
memset(p, alpha, w * h * d);
// Check if we have colormap image...
if (image->red_mask == 0) {
// Get the colormap entries for this window...
maxindex = fl_visual->visual->map_entries;
for (i = 0; i < maxindex; i ++) colors[i].pixel = i;
XQueryColors(fl_display, fl_colormap, colors, maxindex);
for (i = 0; i < maxindex; i ++) {
cvals[i][0] = colors[i].red >> 8;
cvals[i][1] = colors[i].green >> 8;
cvals[i][2] = colors[i].blue >> 8;
}
// Read the pixels and output an RGB image...
for (y = 0; y < image->height; y ++) {
pixel = (unsigned char *)(image->data + y * image->bytes_per_line);
line = p + y * w * d;
switch (image->bits_per_pixel) {
case 1 :
for (x = image->width, line_ptr = line, index_mask = 128;
x > 0;
x --, line_ptr += d) {
if (*pixel & index_mask) {
line_ptr[0] = cvals[1][0];
line_ptr[1] = cvals[1][1];
line_ptr[2] = cvals[1][2];
} else {
line_ptr[0] = cvals[0][0];
line_ptr[1] = cvals[0][1];
line_ptr[2] = cvals[0][2];
}
if (index_mask > 1) {
index_mask >>= 1;
} else {
index_mask = 128;
pixel ++;
}
}
break;
case 2 :
for (x = image->width, line_ptr = line, index_shift = 6;
x > 0;
x --, line_ptr += d) {
i = (*pixel >> index_shift) & 3;
line_ptr[0] = cvals[i][0];
line_ptr[1] = cvals[i][1];
line_ptr[2] = cvals[i][2];
if (index_shift > 0) {
index_mask >>= 2;
index_shift -= 2;
} else {
index_mask = 192;
index_shift = 6;
pixel ++;
}
}
break;
case 4 :
for (x = image->width, line_ptr = line, index_shift = 4;
x > 0;
x --, line_ptr += d) {
if (index_shift == 4) i = (*pixel >> 4) & 15;
else i = *pixel & 15;
line_ptr[0] = cvals[i][0];
line_ptr[1] = cvals[i][1];
line_ptr[2] = cvals[i][2];
if (index_shift > 0) {
index_shift = 0;
} else {
index_shift = 4;
pixel ++;
}
}
break;
case 8 :
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel ++) {
line_ptr[0] = cvals[*pixel][0];
line_ptr[1] = cvals[*pixel][1];
line_ptr[2] = cvals[*pixel][2];
}
break;
case 12 :
for (x = image->width, line_ptr = line, index_shift = 0;
x > 0;
x --, line_ptr += d) {
if (index_shift == 0) {
i = ((pixel[0] << 4) | (pixel[1] >> 4)) & 4095;
} else {
i = ((pixel[1] << 8) | pixel[2]) & 4095;
}
line_ptr[0] = cvals[i][0];
line_ptr[1] = cvals[i][1];
line_ptr[2] = cvals[i][2];
if (index_shift == 0) {
index_shift = 4;
} else {
index_shift = 0;
pixel += 3;
}
}
break;
}
}
} else {
// RGB(A) image, so figure out the shifts & masks...
red_mask = image->red_mask;
red_shift = 0;
while ((red_mask & 1) == 0) {
red_mask >>= 1;
red_shift ++;
}
green_mask = image->green_mask;
green_shift = 0;
while ((green_mask & 1) == 0) {
green_mask >>= 1;
green_shift ++;
}
blue_mask = image->blue_mask;
blue_shift = 0;
while ((blue_mask & 1) == 0) {
blue_mask >>= 1;
blue_shift ++;
}
// Read the pixels and output an RGB image...
for (y = 0; y < image->height; y ++) {
pixel = (unsigned char *)(image->data + y * image->bytes_per_line);
line = p + y * w * d;
switch (image->bits_per_pixel) {
case 8 :
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel ++) {
i = *pixel;
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
break;
case 12 :
for (x = image->width, line_ptr = line, index_shift = 0;
x > 0;
x --, line_ptr += d) {
if (index_shift == 0) {
i = ((pixel[0] << 4) | (pixel[1] >> 4)) & 4095;
} else {
i = ((pixel[1] << 8) | pixel[2]) & 4095;
}
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
if (index_shift == 0) {
index_shift = 4;
} else {
index_shift = 0;
pixel += 3;
}
}
break;
case 16 :
if (image->byte_order == LSBFirst) {
// Little-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 2) {
i = (pixel[1] << 8) | pixel[0];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
} else {
// Big-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 2) {
i = (pixel[0] << 8) | pixel[1];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
}
break;
case 24 :
if (image->byte_order == LSBFirst) {
// Little-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 3) {
i = (((pixel[2] << 8) | pixel[1]) << 8) | pixel[0];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
} else {
// Big-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 3) {
i = (((pixel[0] << 8) | pixel[1]) << 8) | pixel[2];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
}
break;
case 32 :
if (image->byte_order == LSBFirst) {
// Little-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 4) {
i = (((((pixel[3] << 8) | pixel[2]) << 8) | pixel[1]) << 8) | pixel[0];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
} else {
// Big-endian...
for (x = image->width, line_ptr = line;
x > 0;
x --, line_ptr += d, pixel += 4) {
i = (((((pixel[0] << 8) | pixel[1]) << 8) | pixel[2]) << 8) | pixel[3];
line_ptr[0] = 255 * ((i >> red_shift) & red_mask) / red_mask;
line_ptr[1] = 255 * ((i >> green_shift) & green_mask) / green_mask;
line_ptr[2] = 255 * ((i >> blue_shift) & blue_mask) / blue_mask;
}
}
break;
}
}
}
// Destroy the X image we've read and return the RGB(A) image...
XDestroyImage(image);
return p;
}
#endif
//
// End of "$Id: fl_read_image.cxx,v 1.1.1.1 2003/06/03 22:25:46 agno Exp $".
//
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