add ability to pass Color widgets HSV data

This allows for lossless data round-trips through the color picker and
color edit systems, and lets you do things like track hue in
applications even when saturation and/or value are zero.

Fixes ocornut#2383

imgui.h

@@ -1117,16 +1117,20 @@ enum ImGuiColorEditFlags_
     ImGuiColorEditFlags_Float           = 1 << 24,  // [DataType]   // ColorEdit, ColorPicker, ColorButton: _display_ values formatted as 0.0f..1.0f floats instead of 0..255 integers. No round-trip of value via integers.
     ImGuiColorEditFlags_PickerHueBar    = 1 << 25,  // [PickerMode] // ColorPicker: bar for Hue, rectangle for Sat/Value.
     ImGuiColorEditFlags_PickerHueWheel  = 1 << 26,  // [PickerMode] // ColorPicker: wheel for Hue, triangle for Sat/Value.
+    ImGuiColorEditFlags_InputRGB        = 1 << 27,  // [Input]      // ColorEdit, ColorPicker: input and output data is in RGB format
+    ImGuiColorEditFlags_InputHSV        = 1 << 28,  // [Input]      // ColorEdit, ColorPicker: input and output data is in HSV format
+
     // Obsolete names (will be removed)
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     ImGuiColorEditFlags_RGB = ImGuiColorEditFlags_ShowRGB, ImGuiColorEditFlags_HSV = ImGuiColorEditFlags_ShowHSV, ImGuiColorEditFlags_HEX = ImGuiColorEditFlags_ShowHEX,
 #endif
 
     // [Internal] Masks
     ImGuiColorEditFlags__ShowMask       = ImGuiColorEditFlags_ShowRGB|ImGuiColorEditFlags_ShowHSV|ImGuiColorEditFlags_ShowHEX,
+    ImGuiColorEditFlags__InputMask      = ImGuiColorEditFlags_InputRGB|ImGuiColorEditFlags_InputHSV,
     ImGuiColorEditFlags__DataTypeMask   = ImGuiColorEditFlags_Uint8|ImGuiColorEditFlags_Float,
     ImGuiColorEditFlags__PickerMask     = ImGuiColorEditFlags_PickerHueWheel|ImGuiColorEditFlags_PickerHueBar,
-    ImGuiColorEditFlags__OptionsDefault = ImGuiColorEditFlags_Uint8|ImGuiColorEditFlags_ShowRGB|ImGuiColorEditFlags_PickerHueBar    // Change application default using SetColorEditOptions()
+    ImGuiColorEditFlags__OptionsDefault = ImGuiColorEditFlags_Uint8|ImGuiColorEditFlags_ShowRGB|ImGuiColorEditFlags_PickerHueBar|ImGuiColorEditFlags_InputRGB    // Change application default using SetColorEditOptions()
 };
 
 // Enumeration for GetMouseCursor()

imgui_demo.cpp

@@ -1040,6 +1040,9 @@ static void ShowDemoWindowWidgets()
         ImGui::Checkbox("With HDR", &hdr); ImGui::SameLine(); ShowHelpMarker("Currently all this does is to lift the 0..1 limits on dragging widgets.");
         int misc_flags = (hdr ? ImGuiColorEditFlags_HDR : 0) | (drag_and_drop ? 0 : ImGuiColorEditFlags_NoDragDrop) | (alpha_half_preview ? ImGuiColorEditFlags_AlphaPreviewHalf : (alpha_preview ? ImGuiColorEditFlags_AlphaPreview : 0)) | (options_menu ? 0 : ImGuiColorEditFlags_NoOptions);
 
+        ImGui::Text("RGB values:");
+        ImGui::DragFloat4("MyColor##0", (float*)&color.x, 0.01f, 0.0f, 1.0f);
+
         ImGui::Text("Color widget:");
         ImGui::SameLine(); ShowHelpMarker("Click on the colored square to open a color picker.\nCTRL+click on individual component to input value.\n");
         ImGui::ColorEdit3("MyColor##1", (float*)&color, misc_flags);
@@ -1164,6 +1167,16 @@ static void ShowDemoWindowWidgets()
         if (ImGui::Button("Default: Float + HDR + Hue Wheel"))
             ImGui::SetColorEditOptions(ImGuiColorEditFlags_Float | ImGuiColorEditFlags_HDR | ImGuiColorEditFlags_PickerHueWheel);
 
+        ImGui::Spacing();
+        ImGui::Text("HSV-formatted colors");
+        ImGui::SameLine(); ShowHelpMarker("By default, colors are given to ColorEdit and ColorPicker in RGB, but ImGuiColorEditFlags_InputHSV allows you to store colors as HSV and pass them to ColorEdit and ColorPicker as HSV. This comes with the added benefit that you can manipulate hue values with the picker even when saturation or value are zero.");
+
+        static ImVec4 color_stored_as_hsv(0.23f, 1.0f, 1.0f, 1.0f);
+        ImGui::Text("HSV values:");
+        ImGui::DragFloat4("HSVColor##0", (float*)&color_stored_as_hsv, 0.01f, 0.0f, 1.0f);
+        ImGui::Text("Color widget with InputHSV:");
+        ImGui::ColorEdit4("HSVColor##1", (float*)&color_stored_as_hsv, ImGuiColorEditFlags_ShowRGB | ImGuiColorEditFlags_InputHSV);
+
         ImGui::TreePop();
     }