Attempt to fix [Bug 919066] by allowing the code that creates the region

much more knowledge of the platform functions available to it.

1 files changed, 60 insertions, 1 deletions

diff --git a/unix/tkUnix.c b/unix/tkUnix.c
index 0d6ecc5..65f1a90 100644
--- a/unix/tkUnix.c
+++ b/unix/tkUnix.c
@@ -10,7 +10,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tkUnix.c,v 1.5 2002/01/25 21:09:37 dgp Exp $
+ * RCS: @(#) $Id: tkUnix.c,v 1.6 2004/10/26 13:15:09 dkf Exp $
  */
 
 #include <tkInt.h>
@@ -106,3 +106,62 @@ Tk_UpdatePointer(tkwin, x, y, state)
    * This function intentionally left blank
    */
 }
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkpBuildRegionFromAlphaData --
+ *
+ *	Set up a rectangle of the given region based on the supplied
+ *	alpha data.
+ *
+ * Results:
+ *	None
+ *
+ * Side effects:
+ *	The region is updated, with extra pixels added to it.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkpBuildRegionFromAlphaData(region, x, y, width, height, dataPtr,
+	pixelStride, lineStride)
+    TkRegion region;
+    unsigned int x, y;			/* Where in region to update. */
+    unsigned int width, height;		/* Size of rectangle to update. */
+    unsigned char *dataPtr;		/* Data to read from. */
+    unsigned int pixelStride;		/* num bytes from one piece of alpha
+					 * data to the next in the line. */
+    unsigned int lineStride;		/* num bytes from one line of alpha
+					 * data to the next line. */
+{
+    unsigned char *lineDataPtr;
+    unsigned int x1, y1, end;
+    XRectangle rect;
+
+    for (y1 = 0; y1 < height; y1++) {
+	lineDataPtr = dataPtr;
+	for (x1 = 0; x1 < width; x1 = end) {
+	    /* search for first non-transparent pixel */
+	    while ((x1 < width) && !*lineDataPtr) {
+		x1++;
+		lineDataPtr += pixelStride;
+	    }
+	    end = x1;
+	    /* search for first transparent pixel */
+	    while ((end < width) && *lineDataPtr) {
+		end++;
+		lineDataPtr += pixelStride;
+	    }
+	    if (end > x1) {
+		rect.x = x + x1;
+		rect.y = y + y1;
+		rect.width = end - x1;
+		rect.height = 1;
+		TkUnionRectWithRegion(&rect, region, region);
+	    }
+	}
+	dataPtr += lineStride;
+    }
+}