Add GUI scale sliders for Saturn's screens

The title screen, the menus and the HUD menus (emote wheel, shift menu)
each get a scale slider, relative to Minecraft's GUI scale. The HUD
editor stays in GUI pixels.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/main/java/org/saturnclient/ui/SaturnScreen.java

@@ -6,6 +6,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.saturnclient.config.Config;
+import org.saturnclient.config.property.FloatProperty;
 
 public abstract class SaturnScreen {
     /** How long the background blur takes to fade in, in ms */
@@ -14,8 +15,10 @@ public abstract class SaturnScreen {
     public static interface ScreenProvider {
         public void close();
 
+        /** The screen's width in GUI pixels */
         public int getWidth();
 
+        /** The screen's height in GUI pixels */
         public int getHeight();
     }
 
@@ -23,6 +26,10 @@ public abstract class SaturnScreen {
     public int width;
     public int height;
     public String title;
+    /** GUI pixels per Saturn unit, from {@link #getScale()} when the screen was built */
+    public float scale = 0.5f;
+    /** Whether a mouse button is held, so the screen isn't rebuilt under a drag */
+    private boolean mouseDown = false;
 
     // Saturn Screen
     public List<Element> elements = new ArrayList<>();
@@ -51,10 +58,39 @@ public abstract class SaturnScreen {
         return Math.round(Config.backgroundBlur.value * Math.min(elapsed / (float) BLUR_FADE_IN, 1f));
     }
 
+    /**
+     * The GUI scale setting this screen follows; the menu scale unless the
+     * screen is another kind.
+     */
+    protected FloatProperty getScaleSetting() {
+        return Config.menuScale;
+    }
+
+    /**
+     * GUI pixels per Saturn unit. At 1× a Saturn unit is half a GUI pixel.
+     * Enlarging stops where the screen would be smaller than 320x240 GUI
+     * pixels, the least Minecraft's own GUI scale leaves.
+     */
+    public float getScale() {
+        float fit = Math.min(provider.getWidth() / 320f, provider.getHeight() / 240f);
+        return 0.5f * Math.min(getScaleSetting().value, Math.max(1f, fit));
+    }
+
+    /**
+     * Rebuilds the screen if its scale setting changed, once no drag is going
+     * on (the slider being dragged would be replaced).
+     */
+    public void updateScale() {
+        if (!mouseDown && getScale() != scale) {
+            init();
+        }
+    }
+
     public void init() {
         elements.clear();
-        width = provider.getWidth();
-        height = provider.getHeight();
+        scale = getScale();
+        width = (int) (provider.getWidth() / scale);
+        height = (int) (provider.getHeight() / scale);
         Popup.reset(width, height);
         ui(); // abstraction to render the saturn ui and also render extra stuff here
     }
@@ -72,7 +108,7 @@ public abstract class SaturnScreen {
     public void render(RenderScope renderScope, int mouseX, int mouseY, float delta, long elapsed) {
         renderScope.getMatrixStack().push();
 
-        renderScope.getMatrixStack().scale(0.5f, 0.5f);
+        renderScope.getMatrixStack().scale(scale, scale);
 
         ElementRenderer.render(new ArrayList<>(elements), elapsed, renderScope, mouseX, mouseY);
         Popup.render(renderScope, elapsed, mouseX, mouseY);
@@ -85,8 +121,9 @@ public abstract class SaturnScreen {
     // --------------
 
     public boolean mouseClicked(double mouseX, double mouseY, int button) {
-        mouseX *= 2;
-        mouseY *= 2;
+        mouseDown = true;
+        mouseX /= scale;
+        mouseY /= scale;
 
         if (!Popup.mouseClicked(mouseX, mouseY, button)) {
             ElementRenderer.mouseClicked(elements, mouseX, mouseY, button);
@@ -96,8 +133,8 @@ public abstract class SaturnScreen {
     }
 
     public boolean mouseDragged(double mouseX, double mouseY, int button, double deltaX, double deltaY) {
-        mouseX *= 2;
-        mouseY *= 2;
+        mouseX /= scale;
+        mouseY /= scale;
 
         if (!Popup.mouseDragged(mouseX, mouseY, button, deltaX, deltaY)) {
             ElementRenderer.mouseDragged(elements, mouseX, mouseY, button, deltaX, deltaY);
@@ -107,8 +144,9 @@ public abstract class SaturnScreen {
     }
 
     public boolean mouseReleased(double mouseX, double mouseY, int button) {
-        mouseX *= 2;
-        mouseY *= 2;
+        mouseDown = false;
+        mouseX /= scale;
+        mouseY /= scale;
 
         // Everything hears the release, so no element is left thinking it's being dragged.
         Popup.mouseReleased(mouseX, mouseY, button);
@@ -122,8 +160,8 @@ public abstract class SaturnScreen {
             double mouseY,
             double horizontalAmount,
             double verticalAmount) {
-        mouseX *= 2;
-        mouseY *= 2;
+        mouseX /= scale;
+        mouseY /= scale;
 
         if (!Popup.mouseScrolled(mouseX, mouseY, horizontalAmount, verticalAmount)) {
             ElementRenderer.mouseScrolled(elements, mouseX, mouseY, horizontalAmount, verticalAmount);