0002488: Framebuffer bad endianness when loading images

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0002488

NetSurf

Framebuffer-specific

public

2016-12-04 03:53

2019-05-06 13:16

Reporter

Anthony J. Bentley

Assigned To

Severity

major

Reproducibility

always

Status

confirmed

Resolution

open

Platform

PowerPC

OpenBSD

OS Version

Product Version

Target Version

Fixed in Version

Summary

0002488: Framebuffer bad endianness when loading images

Description

When "netsurf-fb -b 8" or "netsurf-fb -b 16" is run on OpenBSD/macppc (big-endian), images are not displayed properly.

All graphics in webpages, and all framebuffer bitmaps including mouse pointer and toolbar buttons, have incorrect colors. (fb-8-16.png)

The problem is partly due to some casts of pixdata from uint8_t[] to uint32_t*:

frontends/framebuffer/fbtk/fbtk.c:fbtk_set_ptr()
frontends/framebuffer/fbtk/bitmap.c:fb_redraw_bitmap()
frontends/framebuffer/framebuffer.c:framebuffer_set_cursor()

Naively putting a byteswap in libnsfb's plotting (naive-byteswap.diff) "fixes" the issue, except it doesn't fix the throbber and it leaves some ghosting after the cursor (fb-8-16-with-naive-byteswap.png).

A better fix is probably to generate uint32_t from the start. This is platform-independent and not very intrusive (better-fix.diff), but only fixes generated/fbtk images, and doesn't help with fetched images (fb-8-16-with-better-fix.png). It's a start, though.

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Fixed in CI build #

Reported in CI build #

URL of problem page

Attached Files

fb-8-16.png (130,366 bytes) 2016-12-04 03:53

fb-8-16.png (130,366 bytes) 2016-12-04 03:53

naive-byteswap.diff (1,497 bytes) 2016-12-04 03:54

$OpenBSD$
--- src/plot/common.c.orig	Sat Dec  3 14:40:51 2016
+++ src/plot/common.c	Sat Dec  3 14:44:00 2016
@@ -450,7 +450,7 @@ bitmap(nsfb_t *nsfb,
         if (alpha) {
                 for (yloop = yoff; yloop < height; yloop += bmp_stride) {
                         for (xloop = 0; xloop < width; xloop++) {
-                                abpixel = pixel[yloop + xloop + xoff];
+                                abpixel = ((pixel[yloop + xloop + xoff] & 0xFF) << 24) | ((pixel[yloop + xloop + xoff] & 0xFF00) << 8) | ((pixel[yloop + xloop + xoff] & 0xFF0000) >> 8) | ((pixel[yloop + xloop + xoff] >> 24) & 0xFF);
                                 if ((abpixel & 0xFF000000) != 0) {
                                         /* pixel is not transparent; have to
                                          * plot something */
@@ -475,7 +475,7 @@ bitmap(nsfb_t *nsfb,
         } else {
                 for (yloop = yoff; yloop < height; yloop += bmp_stride) {
                         for (xloop = 0; xloop < width; xloop++) {
-                                abpixel = pixel[yloop + xloop + xoff];
+                                abpixel = ((pixel[yloop + xloop + xoff] & 0xFF) << 24) | ((pixel[yloop + xloop + xoff] & 0xFF00) << 8) | ((pixel[yloop + xloop + xoff] & 0xFF0000) >> 8) | ((pixel[yloop + xloop + xoff] >> 24) & 0xFF);
                                 *(pvideo + xloop) = colour_to_pixel(
                                                 nsfb, abpixel);
                         }

naive-byteswap.diff (1,497 bytes) 2016-12-04 03:54

fb-8-16-with-naive-byteswap.png (65,222 bytes) 2016-12-04 03:55

fb-8-16-with-naive-byteswap.png (65,222 bytes) 2016-12-04 03:55

better-fix.diff (1,261 bytes) 2016-12-04 03:56

$OpenBSD$
--- frontends/framebuffer/convert_image.c.orig	Sat Nov 19 06:37:41 2016
+++ frontends/framebuffer/convert_image.c	Sat Dec  3 18:08:10 2016
@@ -266,7 +266,7 @@ main(int argc, char **argv)
 	fprintf(f, "#include \"framebuffer/gui.h\"\n");
 	fprintf(f, "#include \"framebuffer/fbtk.h\"\n\n");
 
-	fprintf(f, "static uint8_t %s_pixdata[] = {\n", argv[3]);
+	fprintf(f, "static uint32_t %s_pixdata[] = {\n", argv[3]);
 	for (y = 0; y < HEIGHT; ++y) {
 		unsigned char *rowptr = bitmap_data + (rowstride * y);
 		if (is_cursor) {
@@ -275,10 +275,8 @@ main(int argc, char **argv)
 		}
 		fprintf(f, "\t");
 		for (x = 0; x < WIDTH; ++x) {
-			for (c = 0; c < 4; ++c) {
-				unsigned char b = *rowptr++;
-				fprintf(f, "0x%02x, ", b);
-			}
+			fprintf(f, "0x%02x%02x%02x%02x, ", rowptr[3], rowptr[2], rowptr[1], rowptr[0]);
+			rowptr += 4;
 		}
 		fprintf(f, "\n");
 	}
$OpenBSD$
--- frontends/framebuffer/fbtk.h.orig	Sat Dec  3 18:03:23 2016
+++ frontends/framebuffer/fbtk.h	Sat Dec  3 18:03:25 2016
@@ -69,7 +69,7 @@ typedef struct fbtk_callback_info {
 struct fbtk_bitmap {
         int width;
         int height;
-        uint8_t *pixdata;
+        uint32_t *pixdata;
         bool opaque;
 
         /* The following two are only used for cursors */

better-fix.diff (1,261 bytes) 2016-12-04 03:56

fb-8-16-with-better-patch.png (208,814 bytes) 2016-12-04 03:58

fb-8-16-with-better-patch.png (208,814 bytes) 2016-12-04 03:58

Relationships

Relationships

Notes

~0001467

Vincent Sanders (administrator)

2016-12-31 12:29

will look at sorting this. currently rummaging around for a big endian system to play with.

Notes

Date Modified	Username	Field	Change
Issue History
2016-12-04 03:53	Anthony J. Bentley	New Issue
2016-12-04 03:53	Anthony J. Bentley	File Added: fb-8-16.png
2016-12-04 03:54	Anthony J. Bentley	File Added: naive-byteswap.diff
2016-12-04 03:55	Anthony J. Bentley	File Added: fb-8-16-with-naive-byteswap.png
2016-12-04 03:56	Anthony J. Bentley	File Added: better-fix.diff
2016-12-04 03:58	Anthony J. Bentley	File Added: fb-8-16-with-better-patch.png
2016-12-31 12:29	Vincent Sanders	Note Added: 0001467
2016-12-31 12:29	Vincent Sanders	Assigned To	=> Vincent Sanders
2016-12-31 12:29	Vincent Sanders	Status	new => confirmed
2019-05-06 13:16	Vincent Sanders	Assigned To	Vincent Sanders =>

Issue History