VideoCommon: add graphics mod editor control for displaying a colored box

Source/Core/VideoCommon/GraphicsModEditor/Controls/MiscControls.cpp

@@ -0,0 +1,46 @@
+// Copyright 2024 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "VideoCommon/GraphicsModEditor/Controls/MiscControls.h"
+
+namespace GraphicsModEditor::Controls
+{
+bool ColorButton(const char* label, ImVec2 buttonSize, ImVec4 color)
+{
+  ImGui::PushStyleColor(ImGuiCol_Button, color);
+  bool pressed = ImGui::Button(label, buttonSize);
+
+  // Draw a gradient on top of the button
+  {
+    ImVec2 tl = ImGui::GetItemRectMin();
+    ImVec2 br = ImGui::GetItemRectMax();
+    ImVec2 size = ImGui::GetItemRectSize();
+
+    float k = 0.3f;
+
+    ImVec2 tl_middle(tl.x, tl.y + size.y * (1.f - k));
+    ImVec2 br_middle(br.x, tl.y + size.y * k);
+
+    ImVec4 col_darker(0.f, 0.f, 0.f, 0.2f);
+    ImVec4 col_interm(0.f, 0.f, 0.f, 0.1f);
+    ImVec4 col_transp(0.f, 0.f, 0.f, 0.f);
+
+    ImGui::GetForegroundDrawList()->AddRectFilledMultiColor(
+        tl, br_middle,
+        ImGui::GetColorU32(col_interm),  // upper left
+        ImGui::GetColorU32(col_interm),  // upper right
+        ImGui::GetColorU32(col_transp),  // bottom right
+        ImGui::GetColorU32(col_transp)   // bottom left
+    );
+    ImGui::GetForegroundDrawList()->AddRectFilledMultiColor(
+        tl_middle, br,
+        ImGui::GetColorU32(col_transp),  // upper left
+        ImGui::GetColorU32(col_transp),  // upper right
+        ImGui::GetColorU32(col_darker),  // bottom right
+        ImGui::GetColorU32(col_darker)   // bottom left
+    );
+  }
+  ImGui::PopStyleColor();
+  return pressed;
+}
+}  // namespace GraphicsModEditor::Controls

Source/Core/VideoCommon/GraphicsModEditor/Controls/MiscControls.h

@@ -0,0 +1,12 @@
+// Copyright 2024 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <imgui.h>
+
+namespace GraphicsModEditor::Controls
+{
+// Pulled from the tips and tricks cafe on 2023, credit to pthom
+bool ColorButton(const char* label, ImVec2 buttonSize, ImVec4 color);
+}  // namespace GraphicsModEditor::Controls