Date: Fri, 19 Apr 2019 20:29:49 +0000 (UTC) From: Bruce Evans <bde@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r346416 - head/lib/libvgl Message-ID: <201904192029.x3JKTn8R026912@repo.freebsd.org>
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Author: bde Date: Fri Apr 19 20:29:49 2019 New Revision: 346416 URL: https://svnweb.freebsd.org/changeset/base/346416 Log: Fix copying of overlapping bitmaps. The cases of copying within the screen bitmap and within a single MEMBUF were broken when first source line is before the first destination line and the sub-bitmaps overlap. The fix just copies horizontal lines in reverse order when the first source line is before the first destination line. This switches directions unnecessarily in some cases, but the switch is about as fast as doing a precise detection of overlaps. When the first lines are the same, there can be undetected overlap in the horizontal direction. The old code already handles this mostly accidentally by using bcopy() for MEMBUFs and by copying through a temporary buffer for the screen bitmap although the latter is sub-optimal in direct modes. Modified: head/lib/libvgl/bitmap.c Modified: head/lib/libvgl/bitmap.c ============================================================================== --- head/lib/libvgl/bitmap.c Fri Apr 19 20:23:39 2019 (r346415) +++ head/lib/libvgl/bitmap.c Fri Apr 19 20:29:49 2019 (r346416) @@ -269,7 +269,7 @@ int __VGLBitmapCopy(VGLBitmap *src, int srcx, int srcy, VGLBitmap *dst, int dstx, int dsty, int width, int hight) { - int srcline, dstline; + int srcline, dstline, yend, yextra, ystep; if (srcx>src->VXsize || srcy>src->VYsize || dstx>dst->VXsize || dsty>dst->VYsize) @@ -296,8 +296,17 @@ __VGLBitmapCopy(VGLBitmap *src, int srcx, int srcy, hight=dst->VYsize-dsty; if (width < 0 || hight < 0) return -1; + yend = srcy + hight; + yextra = 0; + ystep = 1; + if (src->Bitmap == dst->Bitmap && srcy < dsty) { + yend = srcy; + yextra = hight - 1; + ystep = -1; + } if (src->Type == MEMBUF) { - for (srcline=srcy, dstline=dsty; srcline<srcy+hight; srcline++, dstline++) { + for (srcline = srcy + yextra, dstline = dsty + yextra; srcline != yend; + srcline += ystep, dstline += ystep) { WriteVerticalLine(dst, dstx, dstline, width, src->Bitmap+(srcline*src->VXsize+srcx)*dst->PixelBytes); } @@ -319,7 +328,8 @@ __VGLBitmapCopy(VGLBitmap *src, int srcx, int srcy, } else { p = buffer; } - for (srcline=srcy, dstline=dsty; srcline<srcy+hight; srcline++, dstline++) { + for (srcline = srcy + yextra, dstline = dsty + yextra; srcline != yend; + srcline += ystep, dstline += ystep) { ReadVerticalLine(src, srcx, srcline, width, p); WriteVerticalLine(dst, dstx, dstline, width, p); }
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