Method TextEx

extern/imgui/imgui_widgets.cpp:150–256

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

void ImGui::TextEx(const char* text, const char* text_end, ImGuiTextFlags flags)
{
    ImGuiWindow* window = GetCurrentWindow();
    if (window->SkipItems)
        return;
    ImGuiContext& g = *GImGui;

    // Accept null ranges
    if (text == text_end)
        text = text_end = "";

    // Calculate length
    const char* text_begin = text;
    if (text_end == NULL)
        text_end = text + strlen(text); // FIXME-OPT

    const ImVec2 text_pos(window->DC.CursorPos.x, window->DC.CursorPos.y + window->DC.CurrLineTextBaseOffset);
    const float wrap_pos_x = window->DC.TextWrapPos;
    const bool wrap_enabled = (wrap_pos_x >= 0.0f);
    if (text_end - text <= 2000 || wrap_enabled)
    {
        // Common case
        const float wrap_width = wrap_enabled ? CalcWrapWidthForPos(window->DC.CursorPos, wrap_pos_x) : 0.0f;
        const ImVec2 text_size = CalcTextSize(text_begin, text_end, false, wrap_width);

        ImRect bb(text_pos, text_pos + text_size);
        ItemSize(text_size, 0.0f);
        if (!ItemAdd(bb, 0))
            return;

        // Render (we don't hide text after ## in this end-user function)
        RenderTextWrapped(bb.Min, text_begin, text_end, wrap_width);
    }
    else
    {
        // Long text!
        // Perform manual coarse clipping to optimize for long multi-line text
        // - From this point we will only compute the width of lines that are visible. Optimization only available when word-wrapping is disabled.
        // - We also don't vertically center the text within the line full height, which is unlikely to matter because we are likely the biggest and only item on the line.
        // - We use memchr(), pay attention that well optimized versions of those str/mem functions are much faster than a casually written loop.
        const char* line = text;
        const float line_height = GetTextLineHeight();
        ImVec2 text_size(0, 0);

        // Lines to skip (can't skip when logging text)
        ImVec2 pos = text_pos;
        if (!g.LogEnabled)
        {
            int lines_skippable = (int)((window->ClipRect.Min.y - text_pos.y) / line_height);
            if (lines_skippable > 0)
            {
                int lines_skipped = 0;
                while (line < text_end && lines_skipped < lines_skippable)
                {
                    const char* line_end = (const char*)memchr(line, '\n', text_end - line);
                    if (!line_end)
                        line_end = text_end;
                    if ((flags & ImGuiTextFlags_NoWidthForLargeClippedText) == 0)