Question: centering window and light theme

[gko]

Hello,

Thank you for druid.

Is this a proper way to center a window?

use druid::widget::Label;
use druid::{AppLauncher, PlatformError, Point, Screen, Size, Widget, WindowDesc};

fn build_ui() -> impl Widget<()> {
    Label::new("")
}

fn main() -> Result<(), PlatformError> {
    let window_size = Size {
        width: 500.0,
        height: 100.0,
    };

    if let Some(primary_display) = Screen::get_monitors()
        .iter()
        .find(|monitor| monitor.is_primary())
    {
        let main_window = WindowDesc::new(build_ui())
            .set_position(Point {
                x: primary_display.virtual_work_rect().center().x - window_size.width / 2.0,
                y: primary_display.virtual_work_rect().center().y - window_size.height / 2.0,
            })
            .window_size(window_size);

        AppLauncher::with_window(main_window)
            .launch(())
            .expect("failed to launch");
    }

    Ok(())
}

And is there any way to set a light theme without setting each color?
By default it is a dark theme:

druid/druid/src/theme.rs

Lines 120 to 185 in 99a8d66

	pub(crate) fn add_to_env(env: Env) -> Env {
	env.adding(WINDOW_BACKGROUND_COLOR, Color::rgb8(0x29, 0x29, 0x29))
	.adding(TEXT_COLOR, Color::rgb8(0xf0, 0xf0, 0xea))
	.adding(DISABLED_TEXT_COLOR, Color::rgb8(0xa0, 0xa0, 0x9a))
	.adding(PLACEHOLDER_COLOR, Color::rgb8(0x80, 0x80, 0x80))
	.adding(PRIMARY_LIGHT, Color::rgb8(0x5c, 0xc4, 0xff))
	.adding(PRIMARY_DARK, Color::rgb8(0x00, 0x8d, 0xdd))
	.adding(PROGRESS_BAR_RADIUS, 4.)
	.adding(BACKGROUND_LIGHT, Color::rgb8(0x3a, 0x3a, 0x3a))
	.adding(BACKGROUND_DARK, Color::rgb8(0x31, 0x31, 0x31))
	.adding(FOREGROUND_LIGHT, Color::rgb8(0xf9, 0xf9, 0xf9))
	.adding(FOREGROUND_DARK, Color::rgb8(0xbf, 0xbf, 0xbf))
	.adding(DISABLED_FOREGROUND_LIGHT, Color::rgb8(0x89, 0x89, 0x89))
	.adding(DISABLED_FOREGROUND_DARK, Color::rgb8(0x6f, 0x6f, 0x6f))
	.adding(BUTTON_DARK, Color::BLACK)
	.adding(BUTTON_LIGHT, Color::rgb8(0x21, 0x21, 0x21))
	.adding(DISABLED_BUTTON_DARK, Color::grey8(0x28))
	.adding(DISABLED_BUTTON_LIGHT, Color::grey8(0x38))
	.adding(BUTTON_BORDER_RADIUS, 4.)
	.adding(BUTTON_BORDER_WIDTH, 2.)
	.adding(BORDER_DARK, Color::rgb8(0x3a, 0x3a, 0x3a))
	.adding(BORDER_LIGHT, Color::rgb8(0xa1, 0xa1, 0xa1))
	.adding(
	SELECTED_TEXT_BACKGROUND_COLOR,
	Color::rgb8(0x43, 0x70, 0xA8),
	)
	.adding(SELECTED_TEXT_INACTIVE_BACKGROUND_COLOR, Color::grey8(0x74))
	.adding(SELECTION_TEXT_COLOR, Color::rgb8(0x00, 0x00, 0x00))
	.adding(CURSOR_COLOR, Color::WHITE)
	.adding(TEXT_SIZE_NORMAL, 15.0)
	.adding(TEXT_SIZE_LARGE, 24.0)
	.adding(BASIC_WIDGET_HEIGHT, 18.0)
	.adding(WIDE_WIDGET_WIDTH, 100.)
	.adding(BORDERED_WIDGET_HEIGHT, 24.0)
	.adding(TEXTBOX_BORDER_RADIUS, 2.)
	.adding(TEXTBOX_BORDER_WIDTH, 1.)
	.adding(TEXTBOX_INSETS, Insets::new(4.0, 4.0, 4.0, 4.0))
	.adding(SCROLLBAR_COLOR, Color::rgb8(0xff, 0xff, 0xff))
	.adding(SCROLLBAR_BORDER_COLOR, Color::rgb8(0x77, 0x77, 0x77))
	.adding(SCROLLBAR_MAX_OPACITY, 0.7)
	.adding(SCROLLBAR_FADE_DELAY, 1500u64)
	.adding(SCROLLBAR_WIDTH, 8.)
	.adding(SCROLLBAR_PAD, 2.)
	.adding(SCROLLBAR_MIN_SIZE, 45.)
	.adding(SCROLLBAR_RADIUS, 5.)
	.adding(SCROLLBAR_EDGE_WIDTH, 1.)
	.adding(WIDGET_PADDING_VERTICAL, 10.0)
	.adding(WIDGET_PADDING_HORIZONTAL, 8.0)
	.adding(WIDGET_CONTROL_COMPONENT_PADDING, 4.0)
	.adding(
	UI_FONT,
	FontDescriptor::new(FontFamily::SYSTEM_UI).with_size(15.0),
	)
	.adding(
	UI_FONT_BOLD,
	FontDescriptor::new(FontFamily::SYSTEM_UI)
	.with_weight(FontWeight::BOLD)
	.with_size(15.0),
	)
	.adding(
	UI_FONT_ITALIC,
	FontDescriptor::new(FontFamily::SYSTEM_UI)
	.with_style(FontStyle::Italic)
	.with_size(15.0),
	)
	}

[xarvic]

Is this a proper way to center a window?

I could not think of a better one right now.

And is there any way to set a light theme without setting each color?

Not at the moment, but theming is being worked on.

[SecondFlight]

It's worth noting that Wayland doesn't allow top-level windows to be positioned. You can still position subwindows relative to their parent windows in Wayland. See here for more info: https://gitlab.freedesktop.org/wayland/wayland/-/issues/183

[santokalayil]

For positioning window to the center of screen I have used this code. Here I kept the window size to half of the screen size and placed in the 1/4 position of the screen

    let main_window = WindowDesc::new(build_root_widget).title(WINDOW_TITLE).window_size(
        (druid::Screen::get_display_rect().size() / 2.0)
        .to_vec2()
    )
    .set_position((druid::Screen::get_display_rect().size() / 4.0).to_vec2().to_point(),)
    .show_titlebar(false);