Internals: Added ImageButtonEx() helper to temporarily bypass ID issu…

…es (ocornut#2464, ocornut#1390)
kjblanchard · Jun 23, 2020 · e0ec69d · e0ec69d
1 parent 1a1dcea
commit e0ec69d
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Showing 2 changed files with 27 additions and 19 deletions.
diff --git a/imgui_internal.h b/imgui_internal.h
@@ -1958,6 +1958,7 @@ namespace ImGui
     IMGUI_API bool          ArrowButtonEx(const char* str_id, ImGuiDir dir, ImVec2 size_arg, ImGuiButtonFlags flags = 0);
     IMGUI_API void          Scrollbar(ImGuiAxis axis);
     IMGUI_API bool          ScrollbarEx(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float* p_scroll_v, float avail_v, float contents_v, ImDrawCornerFlags rounding_corners);
+    IMGUI_API bool          ImageButtonEx(ImGuiID id, ImTextureID texture_id, const ImVec2& size, const ImVec2& uv0, const ImVec2& uv1, const ImVec2& padding, const ImVec4& bg_col, const ImVec4& tint_col); 
     IMGUI_API ImRect        GetWindowScrollbarRect(ImGuiWindow* window, ImGuiAxis axis);
     IMGUI_API ImGuiID       GetWindowScrollbarID(ImGuiWindow* window, ImGuiAxis axis);
     IMGUI_API ImGuiID       GetWindowResizeID(ImGuiWindow* window, int n); // 0..3: corners, 4..7: borders

diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
@@ -981,28 +981,16 @@ void ImGui::Image(ImTextureID user_texture_id, const ImVec2& size, const ImVec2&
     }
 }
 
-// frame_padding < 0: uses FramePadding from style (default)
-// frame_padding = 0: no framing
-// frame_padding > 0: set framing size
-// The color used are the button colors.
-bool ImGui::ImageButton(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0, const ImVec2& uv1, int frame_padding, const ImVec4& bg_col, const ImVec4& tint_col)
+// ImageButton() is flawed as 'id' is always derived from 'texture_id' (see #2464 #1390)
+// We provide this internal helper to write your own variant while we figure out how to redesign the public ImageButton() API.
+bool ImGui::ImageButtonEx(ImGuiID id, ImTextureID texture_id, const ImVec2& size, const ImVec2& uv0, const ImVec2& uv1, const ImVec2& padding, const ImVec4& bg_col, const ImVec4& tint_col)
 {
+    ImGuiContext& g = *GImGui;
     ImGuiWindow* window = GetCurrentWindow();
     if (window->SkipItems)
         return false;
 
-    ImGuiContext& g = *GImGui;
-    const ImGuiStyle& style = g.Style;
-
-    // Default to using texture ID as ID. User can still push string/integer prefixes.
-    // We could hash the size/uv to create a unique ID but that would prevent the user from animating UV.
-    PushID((void*)(intptr_t)user_texture_id);
-    const ImGuiID id = window->GetID("#image");
-    PopID();
-
-    const ImVec2 padding = (frame_padding >= 0) ? ImVec2((float)frame_padding, (float)frame_padding) : style.FramePadding;
     const ImRect bb(window->DC.CursorPos, window->DC.CursorPos + size + padding * 2);
-    const ImRect image_bb(window->DC.CursorPos + padding, window->DC.CursorPos + padding + size);
     ItemSize(bb);
     if (!ItemAdd(bb, id))
         return false;
@@ -1013,14 +1001,33 @@ bool ImGui::ImageButton(ImTextureID user_texture_id, const ImVec2& size, const I
     // Render
     const ImU32 col = GetColorU32((held && hovered) ? ImGuiCol_ButtonActive : hovered ? ImGuiCol_ButtonHovered : ImGuiCol_Button);
     RenderNavHighlight(bb, id);
-    RenderFrame(bb.Min, bb.Max, col, true, ImClamp((float)ImMin(padding.x, padding.y), 0.0f, style.FrameRounding));
+    RenderFrame(bb.Min, bb.Max, col, true, ImClamp((float)ImMin(padding.x, padding.y), 0.0f, g.Style.FrameRounding));
     if (bg_col.w > 0.0f)
-        window->DrawList->AddRectFilled(image_bb.Min, image_bb.Max, GetColorU32(bg_col));
-    window->DrawList->AddImage(user_texture_id, image_bb.Min, image_bb.Max, uv0, uv1, GetColorU32(tint_col));
+        window->DrawList->AddRectFilled(bb.Min + padding, bb.Max - padding, GetColorU32(bg_col));
+    window->DrawList->AddImage(texture_id, bb.Min + padding, bb.Max - padding, uv0, uv1, GetColorU32(tint_col));
 
     return pressed;
 }
 
+// frame_padding < 0: uses FramePadding from style (default)
+// frame_padding = 0: no framing
+// frame_padding > 0: set framing size
+bool ImGui::ImageButton(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0, const ImVec2& uv1, int frame_padding, const ImVec4& bg_col, const ImVec4& tint_col)
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+    if (window->SkipItems)
+        return false;
+
+    // Default to using texture ID as ID. User can still push string/integer prefixes.
+    PushID((void*)(intptr_t)user_texture_id);
+    const ImGuiID id = window->GetID("#image");
+    PopID();
+
+    const ImVec2 padding = (frame_padding >= 0) ? ImVec2((float)frame_padding, (float)frame_padding) : g.Style.FramePadding;
+    return ImageButtonEx(id, user_texture_id, size, uv0, uv1, padding, bg_col, tint_col);
+}
+
 bool ImGui::Checkbox(const char* label, bool* v)
 {
     ImGuiWindow* window = GetCurrentWindow();