imgui_md: change fontsize at runtime

[steve725]

Hello,
is it possible to change (at runtime) the font size of a markdown string that is rendered by imgui_md?

[pthom]

You may change the markdown options by tweaking AddOnParams

imgui_bundle/bindings/imgui_bundle/immapp/immapp_cpp.pyi

Line 140 in 0734c89

with_markdown_options: Optional[ImGuiMd.MarkdownOptions] = None

before starting the app.

[steve725]

Seems I am misunderstanding something. Neither setting the initial font size nor changing the font size of the markdown text is working in the following code.

from imgui_bundle import imgui, immapp, imgui_ctx, hello_imgui, imgui_md
import os

markdown = r"""
Markdown Font Test

Test Test Test Test Test Test

<u>Underline</u>

~~Strikethrough~~
    """


class Globals:
    def __init__(self):
        self.font1 = None
        self.font2 = None
        self.md_options = imgui_md.MarkdownOptions()
        self.default_font_path = os.path.join("fonts/Roboto", "Roboto-Regular.ttf")

    def setup_markdown(self, font_size=20):
        font_opt = imgui_md.MarkdownFontOptions()
        font_opt.font_base_path = self.default_font_path
        font_opt.regular_size = font_size
        self.md_options.font_options = font_opt

    def on_change_md_fontsize(self):
        self.md_options.font_options.regular_size = 30


gl = Globals()


def create_gui():
    gl.setup_markdown()
    with imgui_ctx.begin("Markdown Font Test"):
        imgui.new_line()
        with imgui_ctx.push_font(gl.font1):
            imgui.text("Font 1")
        imgui.new_line()
        imgui.new_line()
        with imgui_ctx.push_font(gl.font2):
            imgui.text("Font 2")
        imgui.new_line()
        imgui.new_line()
        imgui.separator()
        imgui_md.render(markdown)
        imgui.separator()
        imgui.new_line()
        imgui.new_line()
        if imgui.button("Change_Markdown_Font_Size"):
            gl.on_change_md_fontsize()


def main():
    runner_params = hello_imgui.RunnerParams()
    runner_params.app_window_params.window_geometry.size = (800, 600)
    runner_params.app_window_params.window_title = "Font_Test"
    runner_params.callbacks.show_gui = create_gui
    # -----------------------------------------------------------------
    addons = immapp.AddOnsParams()
    addons.with_markdown = True
    addons.with_markdown_options = gl.md_options

    # -----------------------------------------------------------------
    def load_font():
        gl.font1 = hello_imgui.load_font_ttf(gl.default_font_path, 20)
        gl.font2 = hello_imgui.load_font_ttf(gl.default_font_path, 30)

    runner_params.callbacks.load_additional_fonts = load_font
    # -----------------------------------------------------------------
    immapp.run(runner_params, addons)


# ---------------------------------------------------------------------
if __name__ == "__main__":
    main()

[pthom]

"before starting the app" means that you cannot expect your call to setup_markdown() to have any effect in the GUI. You should gave changed the md options before this

def create_gui():
    gl.setup_markdown() # too late!
    ...

[steve725]

Setting up the markdown options after the initialization of addons.with_markdown_options and before running the app also does not affect the markdown font size.

from imgui_bundle import imgui, immapp, imgui_ctx, hello_imgui, imgui_md
import os

markdown = r"""
Markdown Font Test

Test Test Test Test Test Test

<u>Underline</u>

~~Strikethrough~~
    """


class Globals:
    def __init__(self):
        self.font1 = None
        self.font2 = None
        self.md_options = imgui_md.MarkdownOptions()
        self.default_font_path = os.path.join("fonts/Roboto", "Roboto-Regular.ttf")

    def setup_markdown(self, font_size=20):
        font_opt = imgui_md.MarkdownFontOptions()
        font_opt.font_base_path = self.default_font_path
        font_opt.regular_size = font_size
        self.md_options.font_options = font_opt

    def on_change_md_fontsize(self):
        self.md_options.font_options.regular_size = 30


gl = Globals()


def create_gui():
    with imgui_ctx.begin("Markdown Font Test"):
        imgui.new_line()
        with imgui_ctx.push_font(gl.font1):
            imgui.text("Font 1")
        imgui.new_line()
        imgui.new_line()
        with imgui_ctx.push_font(gl.font2):
            imgui.text("Font 2")
        imgui.new_line()
        imgui.new_line()
        imgui.separator()
        imgui_md.render(markdown)
        imgui.separator()
        imgui.new_line()
        imgui.new_line()
        if imgui.button("Change_Markdown_Font_Size"):
            gl.on_change_md_fontsize()


def main():
    runner_params = hello_imgui.RunnerParams()
    runner_params.app_window_params.window_geometry.size = (800, 600)
    runner_params.app_window_params.window_title = "Font_Test"
    runner_params.callbacks.show_gui = create_gui
    # -----------------------------------------------------------------
    addons = immapp.AddOnsParams()
    # addons.with_markdown = True
    addons.with_markdown_options = gl.md_options
    # -----------------------------------------------------------------
    def load_font():
        gl.font1 = hello_imgui.load_font_ttf(gl.default_font_path, 20)
        gl.font2 = hello_imgui.load_font_ttf(gl.default_font_path, 30)

    runner_params.callbacks.load_additional_fonts = load_font
    # -----------------------------------------------------------------
    gl.setup_markdown()
    # -----------------------------------------------------------------
    immapp.run(runner_params, addons)


# ---------------------------------------------------------------------
if __name__ == "__main__":
    main()

[pthom]

Please do more test before writing.

addons.with_markdown_options.font_options.regular_size = 60

before calling immapp.run does work.

The bug is in your code.