Function DemoWindowWidgetsImages

3rdparty/imgui/src/imgui_demo.cpp:1865–1941

//-----------------------------------------------------------------------------

static void DemoWindowWidgetsImages()
{
    if (ImGui::TreeNode("Images"))
    {
        IMGUI_DEMO_MARKER("Widgets/Images");
        ImGuiIO& io = ImGui::GetIO();
        ImGui::TextWrapped(
            "Below we are displaying the font texture (which is the only texture we have access to in this demo). "
            "Use the 'ImTextureID' type as storage to pass pointers or identifier to your own texture data. "
            "Hover the texture for a zoomed view!");

        // Below we are displaying the font texture because it is the only texture we have access to inside the demo!
        // Read description about ImTextureID/ImTextureRef and FAQ for details about texture identifiers.
        // If you use one of the default imgui_impl_XXXX.cpp rendering backend, they all have comments at the top
        // of their respective source file to specify what they are using as texture identifier, for example:
        // - The imgui_impl_dx11.cpp renderer expect a 'ID3D11ShaderResourceView*' pointer.
        // - The imgui_impl_opengl3.cpp renderer expect a GLuint OpenGL texture identifier, etc.
        // So with the DirectX11 backend, you call ImGui::Image() with a 'ID3D11ShaderResourceView*' cast to ImTextureID.
        // - If you decided that ImTextureID = MyEngineTexture*, then you can pass your MyEngineTexture* pointers
        //   to ImGui::Image(), and gather width/height through your own functions, etc.
        // - You can use ShowMetricsWindow() to inspect the draw data that are being passed to your renderer,
        //   it will help you debug issues if you are confused about it.
        // - Consider using the lower-level ImDrawList::AddImage() API, via ImGui::GetWindowDrawList()->AddImage().
        // - Read https://github.com/ocornut/imgui/blob/master/docs/FAQ.md
        // - Read https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples

        // Grab the current texture identifier used by the font atlas.
        ImFontAtlas* atlas = io.Fonts;
        ImTextureRef my_tex_id = atlas->TexRef;
        float my_tex_w = (float)atlas->TexData->Width; // Regular user code should never have to care about TexData-> fields, but since we want to display the entire texture here, we pull Width/Height from it.
        float my_tex_h = (float)atlas->TexData->Height;
        ImGui::Text("%.0fx%.0f", my_tex_w, my_tex_h);

        // Basic drawing
        ImGui::SeparatorText("Image()/ImageWithBg() function");
        ImVec2 uv_min = ImVec2(0.0f, 0.0f); // Top-left
        ImVec2 uv_max = ImVec2(1.0f, 1.0f); // Lower-right
        ImGui::PushStyleVar(ImGuiStyleVar_ImageBorderSize, IM_MAX(1.0f, ImGui::GetStyle().ImageBorderSize));
        ImGui::ImageWithBg(my_tex_id, ImVec2(my_tex_w, my_tex_h), uv_min, uv_max, ImVec4(0.0f, 0.0f, 0.0f, 1.0f));
        ImGui::PopStyleVar();

        // Fancy widget
        ImGui::SeparatorText("Interactive Image Viewer");
        static ExampleImageViewerData image_viewer;
        ImVec2 canvas_size(ImGui::GetContentRegionAvail().x, my_tex_h * 2.0f);
        ExampleImageViewer_DrawOptions(&image_viewer);
        ExampleImageViewer_DrawCanvas(&image_viewer, canvas_size, my_tex_id, (int)my_tex_w, (int)my_tex_h);

        IMGUI_DEMO_MARKER("Widgets/Images/Textured buttons");
        ImGui::SeparatorText("Textured Buttons");
        ImGui::TextWrapped("And now some textured buttons..");
        static int pressed_count = 0;
        for (int i = 0; i < 8; i++)
        {
            // UV coordinates are often (0.0f, 0.0f) and (1.0f, 1.0f) to display an entire textures.
            // Here are trying to display only a 32x32 pixels area of the texture, hence the UV computation.
            // Read about UV coordinates here: https://github.com/ocornut/imgui/wiki/Image-Loading-and-Displaying-Examples
            ImGui::PushID(i);