From c72d5099fecfa3d3e80568172f6b95c085a32565 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9my=20Zurcher?= <jeremy@asynk.ch>
Date: Wed, 18 Dec 2019 23:07:00 +0100
Subject: UI : add Scrollable

---
 core/src/ch/asynk/gdx/boardgame/ui/Scrollable.java | 100 +++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 core/src/ch/asynk/gdx/boardgame/ui/Scrollable.java

diff --git a/core/src/ch/asynk/gdx/boardgame/ui/Scrollable.java b/core/src/ch/asynk/gdx/boardgame/ui/Scrollable.java
new file mode 100644
index 0000000..8484e0e
--- /dev/null
+++ b/core/src/ch/asynk/gdx/boardgame/ui/Scrollable.java
@@ -0,0 +1,100 @@
+package ch.asynk.gdx.boardgame.ui;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.math.Rectangle;
+import com.badlogic.gdx.graphics.GL20;
+import com.badlogic.gdx.graphics.glutils.HdpiUtils;
+import com.badlogic.gdx.graphics.g2d.Batch;
+import com.badlogic.gdx.graphics.g2d.NinePatch;
+
+public class Scrollable extends Element
+{
+    private Element child;
+    private int scissorIdx;
+    private Rectangle clip;
+    public boolean vScroll;
+    public boolean hScroll;
+
+    public Scrollable(Element child)
+    {
+        super();
+        this.vScroll = true;
+        this.hScroll = false;
+        this.child = child;
+        this.scissorIdx = -1;
+        this.clip = new Rectangle();
+    }
+
+    public Element getChild() { return child; }
+
+    public float getBestWidth()
+    {
+        return (child.getWidth() + (2 * padding));
+    }
+
+    public float getBestHeight()
+    {
+        return (child.getHeight() + (2 * padding));
+    }
+
+    @Override public void computeGeometry()
+    {
+        child.computeGeometry();
+    }
+
+    @Override public boolean touch(float x, float y)
+    {
+        return clip.contains(x, y);
+    }
+
+    @Override public boolean drag(float x, float y, int dx, int dy)
+    {
+        if (!touch(x, y)) return false;
+        float tx = 0;
+        float ty = 0;
+        if (vScroll) {
+            if (dy > 0 && child.rect.y < clip.y) {
+                ty = Math.min(dy, clip.y - child.rect.y);
+            }
+            else if (dy < 0) {
+                float cly = clip.y + clip.height;
+                float chy = child.rect.y + child.rect.height;
+                if (chy > cly)
+                    ty = Math.max(dy, cly - chy);
+            }
+        }
+        if (hScroll) {
+            if (dx > 0 && child.rect.x < clip.x) {
+                tx = Math.min(dx, clip.x - child.rect.x);
+            }
+            else if (dx < 0) {
+                float clx = clip.x + clip.width;
+                float chx = child.rect.x + child.rect.width;
+                if (chx > clx)
+                    tx = Math.max(dx, clx - chx);
+            }
+        }
+        child.translate(tx, ty);
+        return true;
+    }
+
+    @Override public void setPosition(float x, float y, float w, float h)
+    {
+        rect.set(x, y, w, h);
+        clip.set((x + padding), (y + padding), (w - 2 * padding), (h - 2 * padding));
+        child.setPosition(clip.x, clip.y - (child.rect.height - clip.height));
+        scissorIdx = Scissors.compute(scissorIdx, clip);
+    }
+
+    @Override public void draw(Batch batch)
+    {
+        if (!visible) return;
+        batch.flush();
+        Rectangle scissor = Scissors.get(scissorIdx, clip);
+        HdpiUtils.glScissor((int)scissor.x, (int)scissor.y, (int)scissor.width, (int)scissor.height);
+        Gdx.gl.glEnable(GL20.GL_SCISSOR_TEST);
+        child.draw(batch);
+        batch.flush();
+        Gdx.gl.glDisable(GL20.GL_SCISSOR_TEST);
+    }
+}
-- 
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