Add experimental option to disable shaders for color selectors (#960)

data/pref.xml

@@ -213,6 +213,7 @@
       <option id="new_blend" type="bool" default="true" />
       <option id="use_native_clipboard" type="bool" default="true" />
       <option id="use_native_file_dialog" type="bool" default="false" />
+      <option id="use_shaders_for_color_selectors" type="bool" default="true" />
       <option id="one_finger_as_mouse_movement" type="bool" default="true" />
       <option id="load_wintab_driver" type="bool" default="false" />
       <option id="flash_layer" type="bool" default="false" />

data/strings/en.ini

@@ -1302,6 +1302,7 @@ new_blend = New layer blending method
 new_render_engine = New render engine for sprite editor
 native_clipboard = Use native clipboard
 native_file_dialog = Use native file dialog
+shaders_for_color_selectors = Use shaders for color selectors
 one_finger_as_mouse_movement = Interpret one finger as mouse movement
 one_finger_as_mouse_movement_tooltip = <<<END
 Only for Windows 8/10 Pointer API: Interprets one finger as mouse movement

data/widgets/options.xml

@@ -511,6 +511,12 @@
           </hbox>
           <check id="native_clipboard" text="@.native_clipboard" />
           <check id="native_file_dialog" text="@.native_file_dialog" />
+          <hbox>
+            <check id="shaders_for_color_selectors"
+                   text="@.shaders_for_color_selectors"
+                   pref="experimental.use_shaders_for_color_selectors" />
+            <link text="(#960)" url="https://github.com/aseprite/aseprite/issues/960" />
+          </hbox>
 	  <hbox id="load_wintab_driver_box">
             <check id="load_wintab_driver2"
                    text="@.load_wintab_driver"

src/app/ui/color_selector.cpp

@@ -17,6 +17,7 @@
 #include "app/color_spaces.h"
 #include "app/color_utils.h"
 #include "app/modules/gfx.h"
+#include "app/pref/preferences.h"
 #include "app/ui/skin/skin_theme.h"
 #include "app/ui/status_bar.h"
 #include "app/util/shader_helpers.h"
@@ -441,8 +442,7 @@ void ColorSelector::onPaint(ui::PaintEvent& ev)
   os::Surface* painterSurface = nullptr;
 
 #if SK_ENABLE_SKSL              // Paint with shaders
-  buildEffects();
-  if (m_mainEffect && m_bottomEffect && m_alphaEffect) {
+  if (buildEffects()) {
     SkCanvas* canvas;
     bool isSRGB;
     // TODO compare both color spaces
@@ -648,8 +648,11 @@ half4 main(vec2 fragcoord) {
 )";
 }
 
-void ColorSelector::buildEffects()
+bool ColorSelector::buildEffects()
 {
+  if (!Preferences::instance().experimental.useShadersForColorSelectors())
+    return false;
+
   if (!m_mainEffect) {
     if (const char* code = getMainAreaShader())
       m_mainEffect = buildEffect(code);
@@ -664,6 +667,8 @@ void ColorSelector::buildEffects()
     if (const char* code = getAlphaBarShader())
       m_alphaEffect = buildEffect(code);
   }
+
+  return (m_mainEffect && m_bottomEffect && m_alphaEffect);
 }
 
 sk_sp<SkRuntimeEffect> ColorSelector::buildEffect(const char* code)

src/app/ui/color_selector.h

@@ -115,7 +115,7 @@ namespace app {
 
 #if SK_ENABLE_SKSL
     static const char* getAlphaBarShader();
-    void buildEffects();
+    bool buildEffects();
     sk_sp<SkRuntimeEffect> buildEffect(const char* code);
 #endif