So, I am trying to get the width and height of my current screen size, by extending GuiScreen. Though, for some reason, it's returning 0 for this.width and this.height. Yet when I made an Openable GUI extend GuiScreen, it returns the correct values. I need the screen width and height to put my custom health bar in the bottom right of the screen. I've tried to call initGui() and setWorldAndResolution() to see if they'd get the width and height, but with no avail.

 

public class GuiOverlay extends GuiScreen {
    private final ResourceLocation bar = new ResourceLocation(Reference.MODID, "textures/blocks/hp_bar.png");

    private final int bar_width = 102, bar_height = 8, hp_height = 6;
    private int hp_width = 100;

    @SubscribeEvent
    public void renderOverlay(RenderGameOverlayEvent event){
        Minecraft mc = Minecraft.getMinecraft();
        mc.renderEngine.bindTexture(bar);
        
	Utils.getLogger().info("Width: " + this.width); // returns 0
        Utils.getLogger().info("Height: " + this.height); // returns 0

        drawTexturedModalRect(width - bar_width, height - bar_height, 0, 0, bar_width, bar_height); // Off the screen due to width/height = 0
        drawTexturedModalRect(width - bar_width, height - bar_height, 1, bar_height + 1, hp_width, hp_height); // Off the screen due to width/height = 0

        mc.renderEngine.bindTexture(ICONS);
    }
}

Any ideas?

Still having trouble with this. Can't find a solution.

If you follow the call hierarchy for the width and height fields you'll see that the main way they are set is with the Minecraft#updateDisplay() method which calls the Minecraft#checkWindowResize() method which calls the Minecraft#resize() method which calls the GuiScreen#onGuiResize() method which calls the GuiScreen#setWorldAndResolution().

 

I think your GUI should get the benefit of that automatically if you register it and open it properly. But if you wanted to force it then the setWorldAndResolution() method should do it assuming you pass the right size (scaled display size) to it.