Fix ocornut#2722 - ColorPicker / ColorEdit Widget Wrong Conversion fr…

…om HSV to RGB Issue is fixed by storing last active color picker color and last hue value when active color picker takes rgb as input. Then if current color picker color matches last active color - hue value will be restored. IDs are not used because ColorEdit4() and ColorWidget4() may call each other in hard-to-predict ways and they both push their own IDs on to the stack. We need hue restoration to happen in entire stack of these widgets if topmost widget used hue restoration. Since these widgets operate on exact same color value - color was chosen as a factor deciding which widgets should restore hue.
rokups · Aug 31, 2019 · a806a3c · a806a3c
1 parent 0537ac0
commit a806a3c
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diff --git a/imgui_internal.h b/imgui_internal.h
@@ -1012,6 +1012,8 @@ struct ImGuiContext
     ImGuiID                 TempInputTextId;                    // Temporary text input when CTRL+clicking on a slider, etc.
     ImGuiColorEditFlags     ColorEditOptions;                   // Store user options for color edit widgets
     ImVec4                  ColorPickerRef;
+    float                   ColorPickerLastHue;
+    float                   ColorPickerLastActiveColor[3];
     bool                    DragCurrentAccumDirty;
     float                   DragCurrentAccum;                   // Accumulator for dragging modification. Always high-precision, not rounded by end-user precision settings
     float                   DragSpeedDefaultRatio;              // If speed == 0.0f, uses (max-min) * DragSpeedDefaultRatio

diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
@@ -4197,7 +4197,12 @@ bool ImGui::ColorEdit4(const char* label, float col[4], ImGuiColorEditFlags flag
     if ((flags & ImGuiColorEditFlags_InputHSV) && (flags & ImGuiColorEditFlags_DisplayRGB))
         ColorConvertHSVtoRGB(f[0], f[1], f[2], f[0], f[1], f[2]);
     else if ((flags & ImGuiColorEditFlags_InputRGB) && (flags & ImGuiColorEditFlags_DisplayHSV))
+    {
+        bool restore_hue = memcmp(g.ColorPickerLastActiveColor, f, sizeof(float) * 3) == 0;
         ColorConvertRGBtoHSV(f[0], f[1], f[2], f[0], f[1], f[2]);
+        if (restore_hue)
+            f[0] = g.ColorPickerLastHue;
+    }
     int i[4] = { IM_F32_TO_INT8_UNBOUND(f[0]), IM_F32_TO_INT8_UNBOUND(f[1]), IM_F32_TO_INT8_UNBOUND(f[2]), IM_F32_TO_INT8_UNBOUND(f[3]) };
 
     bool value_changed = false;
@@ -4324,7 +4329,11 @@ bool ImGui::ColorEdit4(const char* label, float col[4], ImGuiColorEditFlags flag
             for (int n = 0; n < 4; n++)
                 f[n] = i[n] / 255.0f;
         if ((flags & ImGuiColorEditFlags_DisplayHSV) && (flags & ImGuiColorEditFlags_InputRGB))
+        {
+            g.ColorPickerLastHue = f[0];
             ColorConvertHSVtoRGB(f[0], f[1], f[2], f[0], f[1], f[2]);
+            memcpy(g.ColorPickerLastActiveColor, f, sizeof(float) * 3);
+        }
         if ((flags & ImGuiColorEditFlags_DisplayRGB) && (flags & ImGuiColorEditFlags_InputHSV))
             ColorConvertRGBtoHSV(f[0], f[1], f[2], f[0], f[1], f[2]);
 
@@ -4501,7 +4510,11 @@ bool ImGui::ColorPicker4(const char* label, float col[4], ImGuiColorEditFlags fl
     float H = col[0], S = col[1], V = col[2];
     float R = col[0], G = col[1], B = col[2];
     if (flags & ImGuiColorEditFlags_InputRGB)
+    {
         ColorConvertRGBtoHSV(R, G, B, H, S, V);
+        if (memcmp(g.ColorPickerLastActiveColor, col, sizeof(float) * 3) == 0)
+            H = g.ColorPickerLastHue;
+    }
     else if (flags & ImGuiColorEditFlags_InputHSV)
         ColorConvertHSVtoRGB(H, S, V, R, G, B);
 
@@ -4624,7 +4637,9 @@ bool ImGui::ColorPicker4(const char* label, float col[4], ImGuiColorEditFlags fl
     {
         if (flags & ImGuiColorEditFlags_InputRGB)
         {
+            g.ColorPickerLastHue = H;
             ColorConvertHSVtoRGB(H >= 1.0f ? H - 10 * 1e-6f : H, S > 0.0f ? S : 10*1e-6f, V > 0.0f ? V : 1e-6f, col[0], col[1], col[2]);
+            memcpy(g.ColorPickerLastActiveColor, col, sizeof(float) * 3);
         }
         else if (flags & ImGuiColorEditFlags_InputHSV)
         {
@@ -4677,7 +4692,9 @@ bool ImGui::ColorPicker4(const char* label, float col[4], ImGuiColorEditFlags fl
             R = col[0];
             G = col[1];
             B = col[2];
+            float preserve_hue = H;
             ColorConvertRGBtoHSV(R, G, B, H, S, V);
+            H = preserve_hue;                           // Avoids picker losing hue value for 1 frame glitch.
         }
         else if (flags & ImGuiColorEditFlags_InputHSV)
         {