From 9692c762c5d77b399f974c87f5add30149e9f1cd Mon Sep 17 00:00:00 2001
From: YimingWu <xp8110@outlook.com>
Date: Fri, 7 Feb 2025 23:52:06 +0100
Subject: [PATCH] Fix #110853: UI: Support adjusting color picker with Trackpad

Adds the ability to change Color Picker HSL values with Trackpad using
MOUSEPAN.

Pull Request: https://projects.blender.org/blender/blender/pulls/110928
---
 .../regions/interface_region_color_picker.cc   | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/source/blender/editors/interface/regions/interface_region_color_picker.cc b/source/blender/editors/interface/regions/interface_region_color_picker.cc
index 46a9ec6d0b6..669bfc12890 100644
--- a/source/blender/editors/interface/regions/interface_region_color_picker.cc
+++ b/source/blender/editors/interface/regions/interface_region_color_picker.cc
@@ -20,6 +20,7 @@
 #include "BLI_string.h"
 #include "BLI_utildefines.h"
 
+#include "WM_api.hh"
 #include "WM_types.hh"
 
 #include "RNA_access.hh"
@@ -835,11 +836,18 @@ static int ui_colorpicker_wheel_cb(const bContext * /*C*/, uiBlock *block, const
   /* Increase/Decrease the Color HSV Value component using the mouse wheel. */
   float add = 0.0f;
 
-  if (event->type == WHEELUPMOUSE) {
-    add = 0.05f;
-  }
-  else if (event->type == WHEELDOWNMOUSE) {
-    add = -0.05f;
+  switch (event->type) {
+    case WHEELUPMOUSE:
+      add = 0.05f;
+      break;
+    case WHEELDOWNMOUSE:
+      add = -0.05f;
+      break;
+    case MOUSEPAN:
+      add = 0.005f * WM_event_absolute_delta_y(event) / UI_SCALE_FAC;
+      break;
+    default:
+      break;
   }
 
   if (add != 0.0f) {