Add normal preview support

app/src/main/java/com/hippo/drawable/PreciselyClipDrawable.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2016 Hippo Seven
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hippo.drawable;
+
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.graphics.RectF;
+import android.graphics.drawable.Drawable;
+import android.support.v7.graphics.drawable.DrawableWrapper;
+
+import com.hippo.yorozuya.MathUtils;
+
+public class PreciselyClipDrawable extends DrawableWrapper {
+
+    private final boolean mClip;
+    private RectF mScale;
+    private Rect mTemp;
+
+    public PreciselyClipDrawable(Drawable drawable, int offsetX, int offsetY, int width, int height) {
+        super(drawable);
+        float originWidth = drawable.getIntrinsicWidth();
+        float originHeight = drawable.getIntrinsicHeight();
+
+        if (originWidth <= 0 || originHeight <= 0) {
+            // Can not clip
+            mClip = false;
+        } else {
+            mClip = true;
+            mScale = new RectF();
+            mScale.set(MathUtils.clamp(offsetX / originWidth, 0.0f, 1.0f),
+                    MathUtils.clamp(offsetY / originHeight, 0.0f, 1.0f),
+                    MathUtils.clamp((offsetX + width) / originWidth, 0.0f, 1.0f),
+                    MathUtils.clamp((offsetY + height) / originHeight, 0.0f, 1.0f));
+            mTemp = new Rect();
+        }
+    }
+
+    @Override
+    protected void onBoundsChange(Rect bounds) {
+        if (mClip) {
+            if (!mScale.isEmpty()) {
+                mTemp.left = (int) ((mScale.left * bounds.right - mScale.right * bounds.left) /
+                        (mScale.left * (1 - mScale.right) - mScale.right * (1 - mScale.left)));
+                mTemp.right = (int) (((1 - mScale.right) * bounds.left - (1 - mScale.left) * bounds.right) /
+                        (mScale.left * (1 - mScale.right) - mScale.right * (1 - mScale.left)));
+                mTemp.top = (int) ((mScale.top * bounds.bottom - mScale.bottom * bounds.top) /
+                        (mScale.top * (1 - mScale.bottom) - mScale.bottom * (1 - mScale.top)));
+                mTemp.bottom = (int) (((1 - mScale.bottom) * bounds.top - (1 - mScale.top) * bounds.bottom) /
+                        (mScale.top * (1 - mScale.bottom) - mScale.bottom * (1 - mScale.top)));
+                super.onBoundsChange(mTemp);
+            }
+        } else {
+            super.onBoundsChange(bounds);
+        }
+    }
+
+    @Override
+    public int getIntrinsicWidth() {
+        if (mClip) {
+            return (int) (super.getIntrinsicWidth() * mScale.width());
+        } else {
+            return super.getIntrinsicWidth();
+        }
+    }
+
+    @Override
+    public int getIntrinsicHeight() {
+        if (mClip) {
+            return (int) (super.getIntrinsicHeight() * mScale.height());
+        } else {
+            return super.getIntrinsicHeight();
+        }
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        if (mClip) {
+            if (!mScale.isEmpty()) {
+                int saveCount = canvas.save();
+                canvas.clipRect(getBounds());
+                super.draw(canvas);
+                canvas.restoreToCount(saveCount);
+            }
+        } else {
+            super.draw(canvas);
+        }
+    }
+}