From c5ebeaa3085bef608a1ec76e8e6b24e6e98c428a Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 9 Aug 2015 17:11:53 +0200 Subject: [PATCH] swscale/alphablend: Support SWS_ALPHA_BLEND_CHECKERBOARD Signed-off-by: Michael Niedermayer --- doc/scaler.texi | 3 +++ libswscale/alphablend.c | 27 ++++++++++++++++----------- libswscale/options.c | 1 + libswscale/swscale_internal.h | 1 + 4 files changed, 21 insertions(+), 11 deletions(-) diff --git a/doc/scaler.texi b/doc/scaler.texi index 457347c19b..060a45ca74 100644 --- a/doc/scaler.texi +++ b/doc/scaler.texi @@ -130,6 +130,9 @@ Default value is @samp{none}. @item uniform_color Blend onto a uniform background color +@item checkerboard +Blend onto a checkerboard + @item none No blending diff --git a/libswscale/alphablend.c b/libswscale/alphablend.c index 7c9fe6f372..3bd71bac96 100644 --- a/libswscale/alphablend.c +++ b/libswscale/alphablend.c @@ -32,10 +32,17 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], unsigned off = 1<comp[0].depth_minus1; unsigned shift = desc->comp[0].depth_minus1 + 1; unsigned max = (1<flags & AV_PIX_FMT_FLAG_RGB) ? 1<comp[0].depth_minus1 : 0; + for (plane = 0; plane < plane_count; plane++) { + int a = 0, b = 0; + if (c->alphablend == SWS_ALPHA_BLEND_CHECKERBOARD) { + a = (1<comp[0].depth_minus1)/2; + b = 3*(1<comp[0].depth_minus1)/2; + } + target_table[0][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<comp[0].depth_minus1 : a; + target_table[1][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<comp[0].depth_minus1 : b; + } av_assert0(plane_count == nb_components - 1); if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) { @@ -47,16 +54,15 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], const uint16_t *s = src[plane ] + srcStride[plane] * y; const uint16_t *a = src[plane_count] + srcStride[plane_count] * y; uint16_t *d = dst[plane ] + dstStride[plane] * y; - unsigned target = target_table[plane]; if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) { for (x = 0; x < w; x++) { - unsigned u = s[x]*a[x] + target*(max-a[x]) + off; + unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(max-a[x]) + off; d[x] = av_clip((u + (u >> shift)) >> shift, 0, max); } } else { for (x = 0; x < w; x++) { unsigned aswap =av_bswap16(a[x]); - unsigned u = av_bswap16(s[x])*aswap + target*(max-aswap) + off; + unsigned u = av_bswap16(s[x])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off; d[x] = av_clip((u + (u >> shift)) >> shift, 0, max); } } @@ -64,9 +70,8 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], const uint8_t *s = src[plane ] + srcStride[plane] * y; const uint8_t *a = src[plane_count] + srcStride[plane_count] * y; uint8_t *d = dst[plane ] + dstStride[plane] * y; - unsigned target = target_table[plane]; for (x = 0; x < w; x++) { - unsigned u = s[x]*a[x] + target*(255-a[x]) + 128; + unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(255-a[x]) + 128; d[x] = (257*u) >> 16; } } @@ -84,7 +89,7 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], for (x = 0; x < w; x++) { for (plane = 0; plane < plane_count; plane++) { int x_index = (plane_count + 1) * x; - unsigned u = s[x_index + plane]*a[x_index] + target_table[plane]*(max-a[x_index]) + off; + unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(max-a[x_index]) + off; d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max); } } @@ -93,7 +98,7 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], for (plane = 0; plane < plane_count; plane++) { int x_index = (plane_count + 1) * x; unsigned aswap =av_bswap16(a[x_index]); - unsigned u = av_bswap16(s[x_index + plane])*aswap + target_table[plane]*(max-aswap) + off; + unsigned u = av_bswap16(s[x_index + plane])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off; d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max); } } @@ -105,7 +110,7 @@ int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[], for (x = 0; x < w; x++) { for (plane = 0; plane < plane_count; plane++) { int x_index = (plane_count + 1) * x; - unsigned u = s[x_index + plane]*a[x_index] + target_table[plane]*(255-a[x_index]) + 128; + unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(255-a[x_index]) + 128; d[plane_count*x + plane] = (257*u) >> 16; } } diff --git a/libswscale/options.c b/libswscale/options.c index 6ad6cbda2d..18a6594f65 100644 --- a/libswscale/options.c +++ b/libswscale/options.c @@ -81,6 +81,7 @@ static const AVOption swscale_options[] = { { "alphablend", "mode for alpha -> non alpha", OFFSET(alphablend),AV_OPT_TYPE_INT, { .i64 = SWS_ALPHA_BLEND_NONE}, 0, SWS_ALPHA_BLEND_NB-1, VE, "alphablend" }, { "none", "ignore alpha", 0, AV_OPT_TYPE_CONST, { .i64 = SWS_ALPHA_BLEND_NONE}, INT_MIN, INT_MAX, VE, "alphablend" }, { "uniform_color", "blend onto a uniform color", 0, AV_OPT_TYPE_CONST, { .i64 = SWS_ALPHA_BLEND_UNIFORM},INT_MIN, INT_MAX, VE, "alphablend" }, + { "checkerboard", "blend onto a checkerboard", 0, AV_OPT_TYPE_CONST, { .i64 = SWS_ALPHA_BLEND_CHECKERBOARD},INT_MIN, INT_MAX, VE, "alphablend" }, { NULL } }; diff --git a/libswscale/swscale_internal.h b/libswscale/swscale_internal.h index 01c5ad96ba..852dd94b21 100644 --- a/libswscale/swscale_internal.h +++ b/libswscale/swscale_internal.h @@ -78,6 +78,7 @@ typedef enum SwsDither { typedef enum SwsAlphaBlend { SWS_ALPHA_BLEND_NONE = 0, SWS_ALPHA_BLEND_UNIFORM, + SWS_ALPHA_BLEND_CHECKERBOARD, SWS_ALPHA_BLEND_NB, } SwsAlphaBlend;