Bitmap extensions

api/current.txt

@@ -103,7 +103,9 @@ package androidx.graphics {
     method public static android.graphics.Bitmap applyCanvas(android.graphics.Bitmap, kotlin.jvm.functions.Function1<? super android.graphics.Canvas,kotlin.Unit> block);
     method public static android.graphics.Bitmap createBitmap(int width, int height, android.graphics.Bitmap.Config config = "Bitmap.Config.ARGB_8888");
     method @RequiresApi(26) public static android.graphics.Bitmap createBitmap(int width, int height, android.graphics.Bitmap.Config config = "Bitmap.Config.ARGB_8888", boolean hasAlpha = "true", android.graphics.ColorSpace colorSpace = "ColorSpace.get(ColorSpace.Named.SRGB)");
+    method public static android.graphics.Bitmap! crop(android.graphics.Bitmap, int x, int y, int width, int height);
     method public static operator int get(android.graphics.Bitmap, int x, int y);
+    method public static android.graphics.Bitmap! rotate(android.graphics.Bitmap, float degrees, float px = "width / 2.0f", float py = "height / 2.0f");
     method public static android.graphics.Bitmap scale(android.graphics.Bitmap, int width, int height, boolean filter = "true");
     method public static operator void set(android.graphics.Bitmap, int x, int y, @ColorInt int color);
   }

src/androidTest/java/androidx/graphics/BitmapTest.kt

@@ -68,4 +68,24 @@ class BitmapTest {
         b[1, 1] = 0x40302010
         assertEquals(0x40302010, b[1, 1])
     }
+
+    @Test fun crop() {
+        val src = createBitmap(10, 10)
+        src[3, 5] = 0x40302010
+        val res = src.crop(3, 5, 2, 2)
+        assertEquals(2, res.width)
+        assertEquals(2, res.height)
+        assertEquals(0x40302010, res[0, 0])
+    }
+
+    @Test fun rotate() {
+        val src = createBitmap(10, 10)
+        src[3, 5] = 0x40302010
+        src[0, 0] = 0x10203010
+        val res = src.rotate(90f, 0f, 0f)
+        assertEquals(10, res.width)
+        assertEquals(10, res.height)
+        assertEquals(0x10203010, res[9, 0])
+        assertEquals(0x40302010, res[4, 3])
+    }
 }

src/main/java/androidx/graphics/Bitmap.kt

@@ -19,8 +19,10 @@
 package androidx.graphics
 
 import android.graphics.Bitmap
+import android.graphics.Bitmap.createBitmap
 import android.graphics.Canvas
 import android.graphics.ColorSpace
+import android.graphics.Matrix
 import android.support.annotation.ColorInt
 import android.support.annotation.RequiresApi
 
@@ -111,3 +113,30 @@ inline fun createBitmap(
 ): Bitmap {
     return Bitmap.createBitmap(width, height, config, hasAlpha, colorSpace)
 }
+
+/**
+ * Creates a new bitmap, cropped from this bitmap. If the specified [x], [y],
+ * [width], [height] are the same as the current width and height of this bitmap,
+ * this bitmap is returned and no new bitmap is created.
+ *
+ * @param x The x coordinate of the first pixel.
+ * @param y The y coordinate of the first pixel.
+ * @param width The width.
+ * @param height The height.
+ * @return the cropped bitmap
+ */
+inline fun Bitmap.crop(x: Int, y: Int, width: Int, height: Int) =
+    Bitmap.createBitmap(this, x, y, width, height)
+
+/**
+ * Creates a new bitmap, rotated from this bitmap by [degrees] - the specified number of degrees,
+ * with a pivot point at ([px], [py]). The pivot point is the coordinate that should remain
+ * unchanged by the specified transformation.
+ *
+ * @param degrees The number of degrees.
+ * @param px The x coordinate of the pivot point.
+ * @param py The y coordinate of the pivot point.
+ * @return the rotated bitmap
+ */
+inline fun Bitmap.rotate(degrees: Float, px: Float = width / 2.0f, py: Float = height / 2.0f) =
+    createBitmap(this, 0, 0, width, height, Matrix().apply { setRotate(degrees, px, py) }, true)