Attachment 3141 Details for Bug 4321 – Second attempt

[patch] Second attempt

cairo-endian-swap-2.patch (text/plain), 5.90 KB, created by Owen Taylor on 2005-08-31 13:14:03 UTC

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Creator: Owen Taylor

Created: 2005-08-31 13:14:03 UTC

Size: 5.90 KB

patch

obsolete

>Index: ChangeLog
>===================================================================
>RCS file: /cvs/cairo/cairo/ChangeLog,v
>retrieving revision 1.1023
>diff -u -p -r1.1023 ChangeLog
>--- ChangeLog	30 Aug 2005 17:50:27 -0000	1.1023
>+++ ChangeLog	31 Aug 2005 20:10:58 -0000
>@@ -1,3 +1,10 @@
>+2005-08-31  Owen Taylor  <otaylor@redhat.com>
>+
>+	* src/cairo-xlib-surface.c (_get_image_surface) 
>+	(_draw_image_surface): Handle displays which don't match
>+	the local endianness by byteswapping on GetImage/PutImage.
>+	(#4321, reported by Sjoerd Simons)
>+
> 2005-08-30  Owen Taylor  <otaylor@redhat.com>
> 
> 	* src/cairo-xlib-surface.c (_cairo_xlib_surface_create_internal):
>Index: src/cairo-xlib-surface.c
>===================================================================
>RCS file: /cvs/cairo/cairo/src/cairo-xlib-surface.c,v
>retrieving revision 1.118
>diff -u -p -r1.118 cairo-xlib-surface.c
>--- src/cairo-xlib-surface.c	30 Aug 2005 17:50:27 -0000	1.118
>+++ src/cairo-xlib-surface.c	31 Aug 2005 20:10:58 -0000
>@@ -60,6 +60,9 @@ _cairo_xlib_surface_ensure_dst_picture (
> static cairo_bool_t
> _cairo_surface_is_xlib (cairo_surface_t *surface);
> 
>+static cairo_bool_t
>+_native_byte_order_lsb (void);
>+
> /*
>  * Instead of taking two round trips for each blending request,
>  * assume that if a particular drawable fails GetImage that it will
>@@ -302,6 +305,118 @@ _CAIRO_MASK_FORMAT (cairo_format_masks_t
>     return False;
> }
> 
>+static void
>+_swap_ximage_2bytes (XImage *ximage)
>+{
>+    int i, j;
>+    char *line = ximage->data;
>+
>+    for (j = ximage->height; j; j--) {
>+	uint16_t *p = (uint16_t *)line;
>+	for (i = ximage->width; i; i--) {
>+	    *p = (((*p & 0x00ff) << 8) |
>+		  ((*p)          >> 8));
>+	    p++;
>+	}
>+
>+	line += ximage->bytes_per_line;
>+    }
>+}
>+
>+static void
>+_swap_ximage_4bytes (XImage *ximage)
>+{
>+    int i, j;
>+    char *line = ximage->data;
>+
>+    for (j = ximage->height; j; j--) {
>+	uint32_t *p = (uint32_t *)line;
>+	for (i = ximage->width; i; i--) {
>+	    *p = (((*p & 0x000000ff) << 24) |
>+		  ((*p & 0x0000ff00) << 8) |
>+		  ((*p & 0x00ff0000) >> 8) |
>+		  ((*p)              >> 24));
>+	    p++;
>+	}
>+
>+	line += ximage->bytes_per_line;
>+    }
>+}
>+
>+static void
>+_swap_ximage_bits (XImage *ximage)
>+{
>+    int i, j;
>+    char *line = ximage->data;
>+    int unit = ximage->bitmap_unit;
>+    int line_bytes = ((ximage->width + unit - 1) & ~(unit - 1)) / 8;
>+
>+    for (j = ximage->height; j; j--) {
>+	char *p = line;
>+	
>+	for (i = line_bytes; i; i--) {
>+	    char b = *p;
>+	    b = ((b << 1) & 0xaa) | ((b >> 1) & 0x55);
>+	    b = ((b << 2) & 0xcc) | ((b >> 2) & 0x33);
>+	    b = ((b << 4) & 0xf0) | ((b >> 4) & 0x0f);
>+	    *p = b;
>+	    
>+	    p++;
>+	}
>+
>+	line += ximage->bytes_per_line;
>+    }
>+}
>+
>+static void
>+_swap_ximage_to_native (XImage *ximage)
>+{
>+    int unit_bytes = 0;
>+    int native_byte_order = _native_byte_order_lsb () ? LSBFirst : MSBFirst;
>+
>+    if (ximage->bits_per_pixel == 1 &&
>+	ximage->bitmap_bit_order != native_byte_order) {
>+	_swap_ximage_bits (ximage);
>+	if (ximage->bitmap_bit_order == ximage->byte_order)
>+	    return;
>+    }
>+    
>+    if (ximage->byte_order == native_byte_order)
>+	return;
>+
>+    switch (ximage->bits_per_pixel) {
>+    case 1:
>+	unit_bytes = ximage->bitmap_unit / 8;
>+	break;
>+    case 2:
>+    case 4:
>+	/* pixman can't actually handle these formats, but we can
>+	 * byte-swap them anyways ... */
>+	unit_bytes = 1;	
>+	break;
>+    case 8:
>+    case 16:
>+    case 32:
>+	unit_bytes = ximage->bits_per_pixel / 8;
>+	break;
>+    default:
>+	ASSERT_NOT_REACHED;
>+    }
>+
>+    switch (unit_bytes) {
>+    case 1:
>+	return;
>+    case 2:
>+	_swap_ximage_2bytes (ximage);
>+	break;
>+    case 4:
>+	_swap_ximage_4bytes (ximage);
>+	break;
>+    default:
>+	ASSERT_NOT_REACHED;
>+    }
>+}
>+
> static cairo_status_t
> _get_image_surface (cairo_xlib_surface_t   *surface,
> 		    cairo_rectangle_t      *interest_rect,
>@@ -405,6 +520,8 @@ _get_image_surface (cairo_xlib_surface_t
>     }
>     if (!ximage)
> 	return CAIRO_STATUS_NO_MEMORY;
>+
>+    _swap_ximage_to_native (ximage);
> 					
>     /*
>      * Compute the pixel format masks from either a visual or a 
>@@ -545,40 +662,35 @@ _draw_image_surface (cairo_xlib_surface_
> 		     int                    dst_x,
> 		     int                    dst_y)
> {
>-    XImage *ximage;
>-    unsigned bitmap_pad;
>-
>-    /* XXX this is wrong */
>-    if (image->depth > 16)
>-	bitmap_pad = 32;
>-    else if (image->depth > 8)
>-	bitmap_pad = 16;
>-    else
>-	bitmap_pad = 8;
>-
>-    ximage = XCreateImage (surface->dpy,
>-			   DefaultVisual(surface->dpy, DefaultScreen(surface->dpy)),
>-			   image->depth,
>-			   ZPixmap,
>-			   0,
>-			   (char *) image->data,
>-			   image->width,
>-			   image->height,
>-			   bitmap_pad,
>-			   image->stride);
>-    if (ximage == NULL)
>-	return CAIRO_STATUS_NO_MEMORY;
>+    XImage ximage;
>+    int bpp, alpha, red, green, blue;
>+    int native_byte_order = _native_byte_order_lsb () ? LSBFirst : MSBFirst;
>+    
>+    pixman_format_get_masks (pixman_image_get_format (image->pixman_image),
>+			     &bpp, &alpha, &red, &green, &blue);
>+    
>+    ximage.width = image->width;
>+    ximage.height = image->height;
>+    ximage.format = ZPixmap;
>+    ximage.data = (char *)image->data;
>+    ximage.byte_order = native_byte_order;
>+    ximage.bitmap_unit = 32;	/* always for libpixman */
>+    ximage.bitmap_bit_order = native_byte_order;
>+    ximage.bitmap_pad = 32;	/* always for libpixman */
>+    ximage.depth = image->depth;
>+    ximage.bytes_per_line = image->stride;
>+    ximage.bits_per_pixel = bpp;
>+    ximage.red_mask = red;
>+    ximage.green_mask = green;
>+    ximage.blue_mask = blue;
> 
>+    XInitImage (&ximage);
>+    
>     _cairo_xlib_surface_ensure_gc (surface);
>     XPutImage(surface->dpy, surface->drawable, surface->gc,
>-	      ximage, 0, 0, dst_x, dst_y,
>+	      &ximage, 0, 0, dst_x, dst_y,
> 	      image->width, image->height);
> 
>-    /* Foolish XDestroyImage thinks it can free my data, but I won't
>-       stand for it. */
>-    ximage->data = NULL;
>-    XDestroyImage (ximage);
>-
>     return CAIRO_STATUS_SUCCESS;
> 
> }

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