From 8ebcff91118e7b533318b6244d58143da347ce10 Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Wed, 29 Sep 2021 19:10:29 +0200
Subject: [PATCH] avfilter/vf_blend: add geometric mode

---
 doc/filters.texi          | 1 +
 libavfilter/blend.h       | 1 +
 libavfilter/blend_modes.c | 4 ++++
 libavfilter/vf_blend.c    | 2 ++
 4 files changed, 8 insertions(+)

diff --git a/doc/filters.texi b/doc/filters.texi
index b7912b6567..9bac3feb33 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -7543,6 +7543,7 @@ Available values for component modes are:
 @item freeze
 @item exclusion
 @item extremity
+@item geometric
 @item glow
 @item hardlight
 @item hardmix
diff --git a/libavfilter/blend.h b/libavfilter/blend.h
index a9a436a6da..a955126687 100644
--- a/libavfilter/blend.h
+++ b/libavfilter/blend.h
@@ -60,6 +60,7 @@ enum BlendMode {
     BLEND_FREEZE,
     BLEND_EXTREMITY,
     BLEND_SOFTDIFFERENCE,
+    BLEND_GEOMETRIC,
     BLEND_NB
 };
 
diff --git a/libavfilter/blend_modes.c b/libavfilter/blend_modes.c
index d75560185c..9236559d19 100644
--- a/libavfilter/blend_modes.c
+++ b/libavfilter/blend_modes.c
@@ -52,6 +52,7 @@
 #undef SCREEN
 #undef BURN
 #undef DODGE
+#undef GEOMETRIC
 #undef INT2FLOAT
 #undef FLOAT2INT
 #undef MDIV
@@ -61,6 +62,7 @@
 #define SCREEN(x, a, b)   (MAX - (x) * ((MAX - (a)) * (MAX - (b)) / MAX))
 #define BURN(a, b)        (((a) == 0) ? (a) : FFMAX(0, MAX - ((MAX - (b)) << DEPTH) / (a)))
 #define DODGE(a, b)       (((a) == MAX) ? (a) : FFMIN(MAX, (((b) << DEPTH) / (MAX - (a)))))
+#define GEOMETRIC(a, b)   (lrintf(sqrtf((unsigned)A * B)))
 #define INT2FLOAT(x)  (x)
 #define FLOAT2INT(x)  (x)
 #define MDIV (0.125f * (1 << DEPTH))
@@ -69,6 +71,7 @@
 #define SCREEN(x, a, b)   (1.0 - (x) * ((1.0 - (a)) * (1.0 - (b)) / 1.0))
 #define BURN(a, b)        (((a) <= 0.0) ? (a) : FFMAX(0.0, 1.0 - (1.0 - (b)) / (a)))
 #define DODGE(a, b)       (((a) >= 1.0) ? (a) : FFMIN(1.0, ((b) / (1.0 - (a)))))
+#define GEOMETRIC(a, b)   (sqrtf(fmaxf(A, 0) * fmaxf(B, 0)))
 #define INT2FLOAT(x) av_int2float(x)
 #define FLOAT2INT(x) av_float2int(x)
 #define MDIV 0.125f
@@ -140,3 +143,4 @@ fn(xor,        INT2FLOAT(FLOAT2INT(A) ^ FLOAT2INT(B)))
 fn(vividlight, (A < HALF) ? BURN(2 * A, B) : DODGE(2 * (A - HALF), B))
 fn(linearlight,CLIP((B < HALF) ? B + 2 * A - MAX : B + 2 * (A - HALF)))
 fn(softdifference,CLIP((A > B) ? (B == MAX) ? 0 : (A - B) * MAX / (MAX - B) : (B == 0) ? 0 : (B - A) * MAX / B))
+fn(geometric,  GEOMETRIC(A, B))
diff --git a/libavfilter/vf_blend.c b/libavfilter/vf_blend.c
index 43595a1363..c00fb12839 100644
--- a/libavfilter/vf_blend.c
+++ b/libavfilter/vf_blend.c
@@ -132,6 +132,7 @@ static const AVOption blend_options[] = {
     { "vividlight", "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_VIVIDLIGHT}, 0, 0, FLAGS, "mode" },
     { "xor",        "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_XOR},        0, 0, FLAGS, "mode" },
     { "softdifference","", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_SOFTDIFFERENCE}, 0, 0, FLAGS, "mode" },
+    { "geometric",  "", 0, AV_OPT_TYPE_CONST, {.i64=BLEND_GEOMETRIC},  0, 0, FLAGS, "mode" },
     { "c0_expr",  "set color component #0 expression", OFFSET(params[0].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
     { "c1_expr",  "set color component #1 expression", OFFSET(params[1].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
     { "c2_expr",  "set color component #2 expression", OFFSET(params[2].expr_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS },
@@ -396,6 +397,7 @@ static av_cold void init_blend_func_##depth##_##nbits##bit(FilterParams *param)
     case BLEND_VIVIDLIGHT:   param->blend = blend_vividlight_##depth##bit;   break;   \
     case BLEND_XOR:          param->blend = blend_xor_##depth##bit;          break;   \
     case BLEND_SOFTDIFFERENCE:param->blend = blend_softdifference_##depth##bit; break;\
+    case BLEND_GEOMETRIC:    param->blend = blend_geometric_##depth##bit;    break;   \
     }                                                                                 \
 }
 DEFINE_INIT_BLEND_FUNC(8, 8)