From 1e9f4154b1c98115de52562cffc6a3f7fccd4c77 Mon Sep 17 00:00:00 2001
From: Good Guy <good1.2guy@gmail.com>
Date: Wed, 2 Apr 2025 19:09:52 -0600
Subject: [PATCH] Credit Andrea - add tone_mapping to SYSLIB blendprogram
 plugin for all to use

---
 cinelerra-5.1/plugins/blendprogram/Makefile   |  1 +
 .../plugins/blendprogram/tone_mapping.bp      | 48 +++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 cinelerra-5.1/plugins/blendprogram/tone_mapping.bp

diff --git a/cinelerra-5.1/plugins/blendprogram/Makefile b/cinelerra-5.1/plugins/blendprogram/Makefile
index 539349d9..3da098f8 100644
--- a/cinelerra-5.1/plugins/blendprogram/Makefile
+++ b/cinelerra-5.1/plugins/blendprogram/Makefile
@@ -21,6 +21,7 @@ DLFCN_BP_DIR = $(DLFCN_DIR)/bp
 
 BP_OBJS = \
 	chromakey.bp.so \
+	tone_mapping.bp.so \
 	background.bp.so
 
 BP_SRCS = $(BP_OBJS:.bp.so=.bp)
diff --git a/cinelerra-5.1/plugins/blendprogram/tone_mapping.bp b/cinelerra-5.1/plugins/blendprogram/tone_mapping.bp
new file mode 100644
index 00000000..f64fefe8
--- /dev/null
+++ b/cinelerra-5.1/plugins/blendprogram/tone_mapping.bp
@@ -0,0 +1,48 @@
+/*First attach this blend program to your track above the other plugin which
+/you want to make not to clip. Switch clipping off in the blend program
+dialog. This blend program will use the alpha slider (which can have the
+value between 0.0 and 1.0) in the following manner:
+
+0.5 (exactly in the middle): no RGB change
+0.6: R,G,B are multiplied by 2
+0.7: multiplied by 3
+...
+1.0: multiplied by 6
+0.4: multiplied by 1/2 (i.e. divided by 2)
+0.3: multiplied by 1/3
+...
+0.0: multiplied by 1/6 (divided by 6)
+
+If you set it, for example, to 0.4 here, your R,G,B values will be divided
+by 2, so that the color values up to 2.0 will be scaled down into the clip
+range. If you can have values up to, let's say, 5.0, then set the alpha
+slider to 0.1 to scale down by 5, etc.
+
+Then attach the plugin you need to work unclipped, your histogram or
+whatever. Pay attention that all the color values your plugin gets now, are
+scaled down uniformly.
+
+Then attach the same blend program once more, under your needed plugin. This
+time set the alpha slider to 0.6 (if it is 0.4 in the upper une), or to 0.9
+(if the upper one is 0.1), i.e. displace it from the middle in the opposite
+direction. The unclipped values coming from your working plugin will be
+scaled back by the same amount. */
+
+BLEND_PROGRAM_INIT
+
+COLORSPACE_RGB
+PARALLEL_SAFE
+
+BLEND_PROGRAM_PROC
+
+float mult;
+
+mult = KEY_A-0.5;
+if (mult >= 0) mult = 1+mult*10;
+else mult = 1/(1-mult*10);
+
+R(0) = R(0)*mult;
+G(0) = G(0)*mult;
+B(0) = B(0)*mult;
+
+BLEND_PROGRAM_END
-- 
2.26.2