Method RenderTextClippedEx

lib/imgui/imgui.cpp:2356–2382

Default clip_rect uses (pos_min,pos_max) Handle clipping on CPU immediately (vs typically let the GPU clip the triangles that are overlapping the clipping rectangle edges)

// Default clip_rect uses (pos_min,pos_max)
// Handle clipping on CPU immediately (vs typically let the GPU clip the triangles that are overlapping the clipping rectangle edges)
void ImGui::RenderTextClippedEx(ImDrawList* draw_list, const ImVec2& pos_min, const ImVec2& pos_max, const char* text, const char* text_display_end, const ImVec2* text_size_if_known, const ImVec2& align, const ImRect* clip_rect)
{
    // Perform CPU side clipping for single clipped element to avoid using scissor state
    ImVec2 pos = pos_min;
    const ImVec2 text_size = text_size_if_known ? *text_size_if_known : CalcTextSize(text, text_display_end, false, 0.0f);

    const ImVec2* clip_min = clip_rect ? &clip_rect->Min : &pos_min;
    const ImVec2* clip_max = clip_rect ? &clip_rect->Max : &pos_max;
    bool need_clipping = (pos.x + text_size.x >= clip_max->x) || (pos.y + text_size.y >= clip_max->y);
    if (clip_rect) // If we had no explicit clipping rectangle then pos==clip_min
        need_clipping |= (pos.x < clip_min->x) || (pos.y < clip_min->y);

    // Align whole block. We should defer that to the better rendering function when we'll have support for individual line alignment.
    if (align.x > 0.0f) pos.x = ImMax(pos.x, pos.x + (pos_max.x - pos.x - text_size.x) * align.x);
    if (align.y > 0.0f) pos.y = ImMax(pos.y, pos.y + (pos_max.y - pos.y - text_size.y) * align.y);

    // Render
    if (need_clipping)
    {
        ImVec4 fine_clip_rect(clip_min->x, clip_min->y, clip_max->x, clip_max->y);
        draw_list->AddText(NULL, 0.0f, pos, GetColorU32(ImGuiCol_Text), text, text_display_end, 0.0f, &fine_clip_rect);
    }
    else
    {
        draw_list->AddText(NULL, 0.0f, pos, GetColorU32(ImGuiCol_Text), text, text_display_end, 0.0f, NULL);
    }
}

void ImGui::RenderTextClipped(const ImVec2& pos_min, const ImVec2& pos_max, const char* text, const char* text_end, const ImVec2* text_size_if_known, const ImVec2& align, const ImRect* clip_rect)
{