From 9ac9099842a7379a991a70627ddf6fe47462fc4a Mon Sep 17 00:00:00 2001 From: Alexander Larsson Date: Fri, 27 Aug 2010 16:33:35 +0200 Subject: canvas: Better coordinate rounding in scaling When scaling in pixman you give the source coordinates in transformed space rather than in the source coordinates. This is a bit problematic when both source and destination coordinates are at integer positions, but the scaling factor is not an exact 16.16 fixed point value. We used to calculate the transformed source based on the floating point transformation, which gave the wrong answer sometimes. Now we do the calculations based on the fixed point transform that we give pixman. However, even with this patch I can still sometimes see issues related to this, although they are less bad. --- common/sw_canvas.c | 64 ++++++++++++++++++++++++++++++------------------------ 1 file changed, 36 insertions(+), 28 deletions(-) (limited to 'common/sw_canvas.c') diff --git a/common/sw_canvas.c b/common/sw_canvas.c index a4edfa2a..a92cff65 100644 --- a/common/sw_canvas.c +++ b/common/sw_canvas.c @@ -453,16 +453,15 @@ static void __scale_image(SpiceCanvas *spice_canvas, { SwCanvas *canvas = (SwCanvas *)spice_canvas; pixman_transform_t transform; - double sx, sy; + pixman_fixed_t fsx, fsy; + int scaled_src_x, scaled_src_y; - sx = (double)(src_width) / (dest_width); - sy = (double)(src_height) / (dest_height); + fsx = ((pixman_fixed_48_16_t) src_width * 65536) / dest_width; + fsy = ((pixman_fixed_48_16_t) src_height * 65536) / dest_height; pixman_image_set_clip_region32(canvas->image, region); - pixman_transform_init_scale(&transform, - pixman_double_to_fixed(sx), - pixman_double_to_fixed(sy)); + pixman_transform_init_scale(&transform, fsx, fsy); pixman_image_set_transform(src, &transform); pixman_image_set_repeat(src, PIXMAN_REPEAT_NONE); @@ -473,9 +472,12 @@ static void __scale_image(SpiceCanvas *spice_canvas, PIXMAN_FILTER_NEAREST : PIXMAN_FILTER_GOOD, NULL, 0); + scaled_src_x = ((pixman_fixed_48_16_t)src_x * 65536 + fsx/2 ) / fsx; + scaled_src_y = ((pixman_fixed_48_16_t)src_y * 65536 + fsy/2 ) / fsy; + pixman_image_composite32(PIXMAN_OP_SRC, src, NULL, canvas->image, - ROUND(src_x / sx), ROUND(src_y / sy), /* src */ + scaled_src_x, scaled_src_y, /* src */ 0, 0, /* mask */ dest_x, dest_y, /* dst */ dest_width, dest_height); @@ -527,10 +529,11 @@ static void __scale_image_rop(SpiceCanvas *spice_canvas, pixman_image_t *scaled; pixman_box32_t *rects; int n_rects, i; - double sx, sy; + pixman_fixed_t fsx, fsy; + int scaled_src_x, scaled_src_y; - sx = (double)(src_width) / (dest_width); - sy = (double)(src_height) / (dest_height); + fsx = ((pixman_fixed_48_16_t) src_width * 65536) / dest_width; + fsy = ((pixman_fixed_48_16_t) src_height * 65536) / dest_height; scaled = pixman_image_create_bits(spice_pixman_image_get_format(src), dest_width, @@ -540,9 +543,7 @@ static void __scale_image_rop(SpiceCanvas *spice_canvas, pixman_region32_translate(region, -dest_x, -dest_y); pixman_image_set_clip_region32(scaled, region); - pixman_transform_init_scale(&transform, - pixman_double_to_fixed(sx), - pixman_double_to_fixed(sy)); + pixman_transform_init_scale(&transform, fsx, fsy); pixman_image_set_transform(src, &transform); pixman_image_set_repeat(src, PIXMAN_REPEAT_NONE); @@ -553,9 +554,12 @@ static void __scale_image_rop(SpiceCanvas *spice_canvas, PIXMAN_FILTER_NEAREST : PIXMAN_FILTER_GOOD, NULL, 0); + scaled_src_x = ((pixman_fixed_48_16_t)src_x * 65536 + fsx/2 ) / fsx; + scaled_src_y = ((pixman_fixed_48_16_t)src_y * 65536 + fsy/2 ) / fsy; + pixman_image_composite32(PIXMAN_OP_SRC, src, NULL, scaled, - ROUND(src_x / sx), ROUND(src_y / sy), /* src */ + scaled_src_x, scaled_src_y, /* src */ 0, 0, /* mask */ 0, 0, /* dst */ dest_width, @@ -724,18 +728,17 @@ static void __blend_scale_image(SpiceCanvas *spice_canvas, SwCanvas *canvas = (SwCanvas *)spice_canvas; pixman_transform_t transform; pixman_image_t *mask, *dest; - double sx, sy; + pixman_fixed_t fsx, fsy; + int scaled_src_x, scaled_src_y; - sx = (double)(src_width) / (dest_width); - sy = (double)(src_height) / (dest_height); + fsx = ((pixman_fixed_48_16_t) src_width * 65536) / dest_width; + fsy = ((pixman_fixed_48_16_t) src_height * 65536) / dest_height; dest = canvas_get_as_surface(canvas, dest_has_alpha); pixman_image_set_clip_region32(dest, region); - pixman_transform_init_scale(&transform, - pixman_double_to_fixed(sx), - pixman_double_to_fixed(sy)); + pixman_transform_init_scale(&transform, fsx, fsy); mask = NULL; if (overall_alpha != 0xff) { @@ -753,9 +756,12 @@ static void __blend_scale_image(SpiceCanvas *spice_canvas, PIXMAN_FILTER_NEAREST : PIXMAN_FILTER_GOOD, NULL, 0); + scaled_src_x = ((pixman_fixed_48_16_t)src_x * 65536 + fsx/2 ) / fsx; + scaled_src_y = ((pixman_fixed_48_16_t)src_y * 65536 + fsy/2 ) / fsy; + pixman_image_composite32(PIXMAN_OP_OVER, src, mask, dest, - ROUND(src_x / sx), ROUND(src_y / sy), /* src */ + scaled_src_x, scaled_src_y, /* src */ 0, 0, /* mask */ dest_x, dest_y, /* dst */ dest_width, dest_height); @@ -881,10 +887,11 @@ static void __colorkey_scale_image(SpiceCanvas *spice_canvas, pixman_image_t *scaled; pixman_box32_t *rects; int n_rects, i; - double sx, sy; + pixman_fixed_t fsx, fsy; + int scaled_src_x, scaled_src_y; - sx = (double)(src_width) / (dest_width); - sy = (double)(src_height) / (dest_height); + fsx = ((pixman_fixed_48_16_t) src_width * 65536) / dest_width; + fsy = ((pixman_fixed_48_16_t) src_height * 65536) / dest_height; scaled = pixman_image_create_bits(spice_pixman_image_get_format (src), dest_width, @@ -894,9 +901,7 @@ static void __colorkey_scale_image(SpiceCanvas *spice_canvas, pixman_region32_translate(region, -dest_x, -dest_y); pixman_image_set_clip_region32(scaled, region); - pixman_transform_init_scale(&transform, - pixman_double_to_fixed(sx), - pixman_double_to_fixed(sy)); + pixman_transform_init_scale(&transform, fsx, fsy); pixman_image_set_transform(src, &transform); pixman_image_set_repeat(src, PIXMAN_REPEAT_NONE); @@ -904,9 +909,12 @@ static void __colorkey_scale_image(SpiceCanvas *spice_canvas, PIXMAN_FILTER_NEAREST, NULL, 0); + scaled_src_x = ((pixman_fixed_48_16_t)src_x * 65536 + fsx/2 ) / fsx; + scaled_src_y = ((pixman_fixed_48_16_t)src_y * 65536 + fsy/2 ) / fsy; + pixman_image_composite32(PIXMAN_OP_SRC, src, NULL, scaled, - ROUND(src_x / sx), ROUND(src_y / sy), /* src */ + scaled_src_x, scaled_src_y, /* src */ 0, 0, /* mask */ 0, 0, /* dst */ dest_width, -- cgit