+ double begin= timestamp();
+ if (shmim) {
+ xassert( XShmGetImage(disp,id,shmim, 0,0, AllPlanes) );
+ rtimestamp(&begin, "XShmGetImage");
+
+ size_t dsz= shmim->bytes_per_line * shmim->height;
+ im_use= im_free= mmalloc(sizeof(*im_use) + dsz);
+ *im_free= *shmim;
+ im_free->data= (void*)(im_free+1);
+ memcpy(im_free->data, shmim->data, dsz);
+ rtimestamp(&begin, "mmalloc/memcpy");
+ } else {
+ xassert( im_use= im_free=
+ XGetImage(disp,id, 0,0, wwidth,wheight, AllPlanes, ZPixmap) );
+ rtimestamp(&begin, "XGetImage");
+ }
+
+#define COMPUTE_SHIFT_MASK(ix, rgb) \
+ compute_shift_mask(&shiftmasks[ix], im_use->rgb##_mask)
+ COMPUTE_SHIFT_MASK(0, red);
+ COMPUTE_SHIFT_MASK(1, green);
+ COMPUTE_SHIFT_MASK(2, blue);
+
+ if (!*output)
+ *output= alloc_rgb_image(wwidth, wheight);
+
+ rtimestamp(&begin, "compute_shift_masks+alloc_rgb_image");
+
+ int x,y,i;
+ unsigned char *op= (*output)->data;
+ for (y=0; y<wheight; y++) {
+ for (x=0; x<wwidth; x++) {
+ long xrgb= XGetPixel(im_use,x,y);
+ for (i=0; i<3; i++) {
+ unsigned long sample=
+ ((xrgb << shiftmasks[i].lshift) >> shiftmasks[i].rshift)
+ & SAMPLEMASK;
+ *op++= sample;
+ }
+ }
+ }
+
+ rtimestamp(&begin,"w*h*XGetPixel");
+ if (im_free)
+ XDestroyImage(im_free);