On Fri, Jul 15, 2011 at 9:53 PM, Tristan Schmelcher <[email protected]> wrote: > I have a Cairo application that is using Pixman to composite a > semantically opaque image by scaling a bunch of source images in RGB24 > format. If the target surface is also RGB24 format, then it is very > fast and uses fast_composite_scaled_nearest_8888_8888_cover_SRC. But > if the target surface is the ARGB32 format, then it takes almost three > times as long and uses just fast_composite_scaled_nearest. > > If I had a choice, I would always make the destination surface in > RGB24 format, but unfortunately it is being created as ARGB32 by > another library which I don't control, so my application is taking the > slow path. I want to improve it so that the performance in the RGB24 > -> ARGB32 case is approximately as good as the RGB24 -> RGB24 case, if > possible.
Have you tried alternatively converting your opaque source images to ARGB32 format? This approach may have some advantages. > My idea for how to go about this is to add a x888_8888 fast-path to > Pixman for RGB24 -> ARGB32 that does the same thing as the 8888_8888 > path but sets all the destination alpha bytes to 0xFF. But before I > try coding it I wanted to ask here if anyone has any other suggestions > or knows of any "gotchas" with this approach. > > Comments? Yes, this is how pixman development is done at the moment. One finds something that is slow and adds new special fast paths for it. I have also attached a patch which should add the needed entries to the fast path tables. Probably this is what you are intending to get. -- Best regards, Siarhei Siamashka
From cf9290826d83e03b0c466e470eca9b81646af17f Mon Sep 17 00:00:00 2001 From: Siarhei Siamashka <[email protected]> Date: Fri, 15 Jul 2011 23:35:21 +0300 Subject: [PATCH] C fast path for scaled src_x888_8888 with nearest filter The necessity is justified by a message in the pixman mailing list: http://lists.freedesktop.org/archives/pixman/2011-July/001330.html NONE repeat is not supported, but could be added by tweaking the interpretation and making use of 'fully_transparent_src' scanline function argument. --- pixman/pixman-fast-path.c | 10 ++++++++++ pixman/pixman-fast-path.h | 1 + pixman/pixman-private.h | 1 + 3 files changed, 12 insertions(+), 0 deletions(-) diff --git a/pixman/pixman-fast-path.c b/pixman/pixman-fast-path.c index 3c05383..9a6919e 100644 --- a/pixman/pixman-fast-path.c +++ b/pixman/pixman-fast-path.c @@ -1174,6 +1174,9 @@ FAST_NEAREST (8888_8888_cover, 8888, 8888, uint32_t, uint32_t, SRC, COVER) FAST_NEAREST (8888_8888_none, 8888, 8888, uint32_t, uint32_t, SRC, NONE) FAST_NEAREST (8888_8888_pad, 8888, 8888, uint32_t, uint32_t, SRC, PAD) FAST_NEAREST (8888_8888_normal, 8888, 8888, uint32_t, uint32_t, SRC, NORMAL) +FAST_NEAREST (x888_8888_cover, x888, 8888, uint32_t, uint32_t, SRC, COVER) +FAST_NEAREST (x888_8888_pad, x888, 8888, uint32_t, uint32_t, SRC, PAD) +FAST_NEAREST (x888_8888_normal, x888, 8888, uint32_t, uint32_t, SRC, NORMAL) FAST_NEAREST (8888_8888_cover, 8888, 8888, uint32_t, uint32_t, OVER, COVER) FAST_NEAREST (8888_8888_none, 8888, 8888, uint32_t, uint32_t, OVER, NONE) FAST_NEAREST (8888_8888_pad, 8888, 8888, uint32_t, uint32_t, OVER, PAD) @@ -1716,6 +1719,13 @@ static const pixman_fast_path_t c_fast_paths[] = SIMPLE_NEAREST_FAST_PATH (SRC, r5g6b5, r5g6b5, 565_565), + SIMPLE_NEAREST_FAST_PATH_COVER (SRC, x8r8g8b8, a8r8g8b8, x888_8888), + SIMPLE_NEAREST_FAST_PATH_COVER (SRC, x8b8g8r8, a8b8g8r8, x888_8888), + SIMPLE_NEAREST_FAST_PATH_PAD (SRC, x8r8g8b8, a8r8g8b8, x888_8888), + SIMPLE_NEAREST_FAST_PATH_PAD (SRC, x8b8g8r8, a8b8g8r8, x888_8888), + SIMPLE_NEAREST_FAST_PATH_NORMAL (SRC, x8r8g8b8, a8r8g8b8, x888_8888), + SIMPLE_NEAREST_FAST_PATH_NORMAL (SRC, x8b8g8r8, a8b8g8r8, x888_8888), + SIMPLE_NEAREST_FAST_PATH (OVER, a8r8g8b8, x8r8g8b8, 8888_8888), SIMPLE_NEAREST_FAST_PATH (OVER, a8b8g8r8, x8b8g8r8, 8888_8888), SIMPLE_NEAREST_FAST_PATH (OVER, a8r8g8b8, a8r8g8b8, 8888_8888), diff --git a/pixman/pixman-fast-path.h b/pixman/pixman-fast-path.h index e94591a..2b55c2e 100644 --- a/pixman/pixman-fast-path.h +++ b/pixman/pixman-fast-path.h @@ -157,6 +157,7 @@ pad_repeat_get_scanline_bounds (int32_t source_image_width, /* This is not actually used since we don't have an OVER with 565 source, but it is needed to build. */ #define GET_0565_ALPHA(s) 0xff +#define GET_x888_ALPHA(s) 0xff #define FAST_NEAREST_SCANLINE(scanline_func_name, SRC_FORMAT, DST_FORMAT, \ src_type_t, dst_type_t, OP, repeat_mode) \ diff --git a/pixman/pixman-private.h b/pixman/pixman-private.h index 65494c9..6a3935e 100644 --- a/pixman/pixman-private.h +++ b/pixman/pixman-private.h @@ -763,6 +763,7 @@ pixman_region16_copy_from_region32 (pixman_region16_t *dst, /* Trivial versions that are useful in macros */ #define CONVERT_8888_TO_8888(s) (s) +#define CONVERT_x888_TO_8888(s) ((s) | 0xff000000) #define CONVERT_0565_TO_0565(s) (s) #define PIXMAN_FORMAT_IS_WIDE(f) \ -- 1.7.3.4
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