X11: fix .ico cursor bug. Support PNG-compressed .ico files.

doc/ReleaseNotes

@@ -41,6 +41,7 @@ This issue fixes several bugs that were still found in 1.9.2.
 * Fix tinydisplay texture errors on shutdown
 * Fix mipmap filtering issues in tinydisplay renderer
 * Fix exception when creating intervals before ShowBase is started
+* Fix rare X11 .ico cursor bug; also now supports PNG-compressed icons
 
 ------------------------  RELEASE 1.9.2  ------------------------
 

panda/src/x11display/x11GraphicsWindow.cxx

@@ -28,6 +28,8 @@
 #include "nativeWindowHandle.h"
 #include "virtualFileSystem.h"
 #include "get_x11.h"
+#include "pnmImage.h"
+#include "pnmFileTypeRegistry.h"
 
 #include <errno.h>
 #include <fcntl.h>
@@ -2303,11 +2305,41 @@ read_ico(istream &ico) {
   // Seek to the image in the ICO.
   ico.seekg(entries[entry].offset);
   if (!ico.good()) goto cleanup;
+
+  if (ico.peek() == 0x89) {
+    // Hang on, this is actually a PNG header.
+    PNMImage img;
+    PNMFileTypeRegistry *reg = PNMFileTypeRegistry::get_global_ptr();
+    if (!img.read(ico, "", reg->get_type_from_extension("png"))) {
+      goto cleanup;
+    }
+    img.set_maxval(255);
+
+    image = XcursorImageCreate(img.get_x_size(), img.get_y_size());
+
+    xel *ptr = img.get_array();
+    xelval *alpha = img.get_alpha_array();
+    size_t num_pixels = (size_t)img.get_x_size() * (size_t)img.get_y_size();
+    unsigned int *dest = image->pixels;
+
+    if (alpha != NULL) {
+      for (size_t p = 0; p < num_pixels; ++p) {
+        *dest++ = (*alpha << 24U) | (ptr->r << 16U) | (ptr->g << 8U) | (ptr->b);
+        ++ptr;
+        ++alpha;
+      }
+    } else {
+      for (size_t p = 0; p < num_pixels; ++p) {
+        *dest++ = 0xff000000U | (ptr->r << 16U) | (ptr->g << 8U) | (ptr->b);
+        ++ptr;
+      }
+    }
+
+  } else {
     ico.read(reinterpret_cast<char *>(&infoHeader), sizeof(IcoInfoHeader));
     if (!ico.good()) goto cleanup;
     bitsPerPixel = infoHeader.bitsPerPixel;
 
-  // TODO: Support PNG compressed ICOs.
     if (infoHeader.compression != 0) goto cleanup;
 
     // Load the color palette, if one exists.
@@ -2328,12 +2360,9 @@ read_ico(istream &ico) {
     ico.read(andBmp, andBmpSize);
     if (!ico.good()) goto cleanup;
 
-  // If this is an actual CUR not an ICO set up the hotspot properly.
     image = XcursorImageCreate(infoHeader.width, infoHeader.height / 2);
-  if (header.type == 2) { image->xhot = entries[entry].xhot; image->yhot = entries[entry].yhot; }
 
-  // Support all the formats that GIMP supports, minus PNG compressed ICOs.
+    // Support all the formats that GIMP supports.
-  // Would need to use libpng to decode the compressed ones.
     switch (bitsPerPixel) {
     case 1:
     case 4:
@@ -2365,8 +2394,8 @@ read_ico(istream &ico) {
           curAnd++;
         }
       }
-
       break;
+
     case 24:
       // Pack each of the three bytes into a single color, BGR -> 0RGB
       for (i = image->height - 1; i >= 0; i--) {
@@ -2386,10 +2415,9 @@ read_ico(istream &ico) {
 
           curAnd++;
         }
-
       }
-
       break;
+
     case 32:
       // Pack each of the four bytes into a single color, BGRA -> ARGB
       for (i = image->height - 1; i >= 0; i--) {
@@ -2401,11 +2429,20 @@ read_ico(istream &ico) {
           curXor += 4;
         }
       }
-
       break;
+
     default:
       goto cleanup;
-    break;
+    }
+  }
+
+  // If this is an actual CUR not an ICO set up the hotspot properly.
+  if (header.type == 2) {
+    image->xhot = entries[entry].xhot;
+    image->yhot = entries[entry].yhot;
+  } else {
+    image->xhot = 0;
+    image->yhot = 0;
   }
 
   ret = XcursorImageLoadCursor(_display, image);