41 lines
1.4 KiB
C
41 lines
1.4 KiB
C
#include <gd.h>
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void
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setnetwmicon(void)
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{
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/* use a png-image to set _NET_WM_ICON */
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FILE* file = fopen(ICON, "r");
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if (file) {
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/* load image in rgba-format */
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const gdImagePtr icon_rgba = gdImageCreateFromPng(file);
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fclose(file);
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/* declare icon-variable which will store the image in bgra-format */
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const int width = gdImageSX(icon_rgba);
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const int height = gdImageSY(icon_rgba);
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const int icon_n = width * height + 2;
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long icon_bgra[icon_n];
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/* set width and height of the icon */
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int i = 0;
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icon_bgra[i++] = width;
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icon_bgra[i++] = height;
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/* rgba -> bgra */
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for (int y = 0; y < height; y++) {
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for (int x = 0; x < width; x++) {
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const int pixel_rgba = gdImageGetPixel(icon_rgba, x, y);
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unsigned char *pixel_bgra = (unsigned char *) &icon_bgra[i++];
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pixel_bgra[0] = gdImageBlue(icon_rgba, pixel_rgba);
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pixel_bgra[1] = gdImageGreen(icon_rgba, pixel_rgba);
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pixel_bgra[2] = gdImageRed(icon_rgba, pixel_rgba);
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/* scale alpha from 0-127 to 0-255 */
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const unsigned char alpha = 127 - gdImageAlpha(icon_rgba, pixel_rgba);
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pixel_bgra[3] = alpha == 127 ? 255 : alpha * 2;
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}
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}
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gdImageDestroy(icon_rgba);
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/* set _NET_WM_ICON */
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xw.netwmicon = XInternAtom(xw.dpy, "_NET_WM_ICON", False);
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XChangeProperty(xw.dpy, xw.win, xw.netwmicon, XA_CARDINAL, 32,
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PropModeReplace, (uchar *) icon_bgra, icon_n);
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}
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}
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