Function ImFontAtlasBuildRenderBitmapFromString

src/imgui/imgui_draw.cpp:3449–3474

Render a white-colored bitmap encoded in a string

// Render a white-colored bitmap encoded in a string
void ImFontAtlasBuildRenderBitmapFromString(ImFontAtlas* atlas, int x, int y, int w, int h, const char* in_str, char in_marker_char)
{
    ImTextureData* tex = atlas->TexData;
    IM_ASSERT(x >= 0 && x + w <= tex->Width);
    IM_ASSERT(y >= 0 && y + h <= tex->Height);

    switch (tex->Format)
    {
    case ImTextureFormat_Alpha8:
    {
        ImU8* out_p = (ImU8*)tex->GetPixelsAt(x, y);
        for (int off_y = 0; off_y < h; off_y++, out_p += tex->Width, in_str += w)
            for (int off_x = 0; off_x < w; off_x++)
                out_p[off_x] = (in_str[off_x] == in_marker_char) ? 0xFF : 0x00;
        break;
    }
    case ImTextureFormat_RGBA32:
    {
        ImU32* out_p = (ImU32*)tex->GetPixelsAt(x, y);
        for (int off_y = 0; off_y < h; off_y++, out_p += tex->Width, in_str += w)
            for (int off_x = 0; off_x < w; off_x++)
                out_p[off_x] = (in_str[off_x] == in_marker_char) ? IM_COL32_WHITE : IM_COL32_BLACK_TRANS;
        break;
    }
    }
}

static void ImFontAtlasBuildUpdateBasicTexData(ImFontAtlas* atlas)
{