add support for custom Java Drawables

This is made possible, by adding a second Canvas implementation which
can be used to render directly to GdkSnapshot objects

For now the only implemented method is drawBitmap(), this is already
enough to make VectorDrawableCompat functional

meson.build

@@ -97,6 +97,7 @@ libtranslationlayer_so = shared_library('translation_layer_main', [
                                                                   	'src/api-impl-jni/graphics/NinePatchPaintable.c',
                                                                   	'src/api-impl-jni/graphics/NinePatchPaintable.c',
                                                                   	'src/api-impl-jni/graphics/android_graphics_BitmapFactory.c',
+                                                                  	'src/api-impl-jni/graphics/android_graphics_GskCanvas.c',
                                                                   	'src/api-impl-jni/graphics/android_graphics_Matrix.c',
                                                                   	'src/api-impl-jni/graphics/android_graphics_Path.c',
                                                                   	'src/api-impl-jni/graphics/android_graphics_Typeface.c',

src/api-impl-jni/generated_headers/android_graphics_GskCanvas.h

@@ -0,0 +1,21 @@
+/* DO NOT EDIT THIS FILE - it is machine generated */
+#include <jni.h>
+/* Header for class android_graphics_GskCanvas */
+
+#ifndef _Included_android_graphics_GskCanvas
+#define _Included_android_graphics_GskCanvas
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Class:     android_graphics_GskCanvas
+ * Method:    native_drawBitmap
+ * Signature: (JJIIII)V
+ */
+JNIEXPORT void JNICALL Java_android_graphics_GskCanvas_native_1drawBitmap
+  (JNIEnv *, jobject, jlong, jlong, jint, jint, jint, jint);
+
+#ifdef __cplusplus
+}
+#endif
+#endif

src/api-impl-jni/generated_headers/android_graphics_drawable_Drawable.h

@@ -15,6 +15,14 @@ extern "C" {
 JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1paintable_1from_1path
   (JNIEnv *, jclass, jstring);
 
+/*
+ * Class:     android_graphics_drawable_Drawable
+ * Method:    native_constructor
+ * Signature: ()J
+ */
+JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1constructor
+  (JNIEnv *, jobject);
+
 #ifdef __cplusplus
 }
 #endif

src/api-impl-jni/graphics/android_graphics_GskCanvas.c

@@ -0,0 +1,16 @@
+#include <gtk/gtk.h>
+#include <graphene.h>
+
+#include "../defines.h"
+#include "../util.h"
+
+#include "../generated_headers/android_graphics_GskCanvas.h"
+
+JNIEXPORT void JNICALL Java_android_graphics_GskCanvas_native_1drawBitmap(JNIEnv *env, jclass this_class, jlong snapshot_ptr, jlong pixbuf_ptr, jint x, jint y, jint width, jint height)
+{
+	GdkSnapshot *snapshot = (GdkSnapshot *)_PTR(snapshot_ptr);
+	GdkPixbuf *pixbuf = (GdkPixbuf *)_PTR(pixbuf_ptr);
+	GdkTexture *texture = gdk_texture_new_for_pixbuf(pixbuf);
+	gtk_snapshot_append_texture(snapshot, texture, &GRAPHENE_RECT_INIT(x, y, width, height));
+	g_object_unref(texture);
+}

src/api-impl-jni/graphics/android_graphics_drawable_Drawable.c

@@ -2,6 +2,7 @@
 #include <string.h>
 
 #include "../defines.h"
+#include "../util.h"
 #include "NinePatchPaintable.h"
 #include "../generated_headers/android_graphics_drawable_Drawable.h"
 
@@ -20,3 +21,49 @@ JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1paintabl
 	(*env)->ReleaseStringUTFChars(env, pathStr, path);
 	return _INTPTR(paintable);
 }
+
+struct _JavaPaintable {
+	GObject parent_instance;
+	jobject drawable;
+};
+G_DECLARE_FINAL_TYPE(JavaPaintable, java_paintable, JAVA, PAINTABLE, GObject)
+
+static void java_paintable_snapshot(GdkPaintable *gdk_paintable, GdkSnapshot *snapshot, double width, double height)
+{
+	JNIEnv *env = get_jni_env();
+	JavaPaintable *paintable = JAVA_PAINTABLE(gdk_paintable);
+	jclass canvas_class = (*env)->FindClass(env, "android/graphics/GskCanvas");
+	jmethodID canvas_constructor = _METHOD(canvas_class, "<init>", "(J)V");
+	jobject canvas = (*env)->NewObject(env, canvas_class, canvas_constructor, _INTPTR(snapshot));
+	(*env)->CallVoidMethod(env, paintable->drawable, handle_cache.drawable.setBounds, 0, 0, (int)width, (int)height);
+	(*env)->CallVoidMethod(env, paintable->drawable, handle_cache.drawable.draw, canvas);
+	if ((*env)->ExceptionCheck(env))
+		(*env)->ExceptionDescribe(env);
+	(*env)->DeleteLocalRef(env, canvas);
+	(*env)->DeleteLocalRef(env, canvas_class);
+}
+
+static void java_paintable_init(JavaPaintable *java_paintable)
+{
+}
+
+static void java_paintable_paintable_init(GdkPaintableInterface *iface)
+{
+	iface->snapshot = java_paintable_snapshot;
+}
+
+static void java_paintable_class_init(JavaPaintableClass *class)
+{
+}
+
+G_DEFINE_TYPE_WITH_CODE(JavaPaintable, java_paintable, G_TYPE_OBJECT,
+		G_IMPLEMENT_INTERFACE(GDK_TYPE_PAINTABLE, java_paintable_paintable_init))
+
+JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1constructor(JNIEnv *env, jobject this) {
+	JavaPaintable *paintable = NULL;
+	if (handle_cache.drawable.draw != _METHOD(_CLASS(this), "draw", "(Landroid/graphics/Canvas;)V")) {
+		paintable = g_object_new(java_paintable_get_type(), NULL);
+		paintable->drawable = _REF(this);
+	}
+	return _INTPTR(paintable);
+}

src/api-impl-jni/util.c

@@ -144,6 +144,10 @@ void set_up_handle_cache(JNIEnv *env)
 
 	handle_cache.key_event.class = _REF((*env)->FindClass(env, "android/view/KeyEvent"));
 	handle_cache.key_event.constructor = _METHOD(handle_cache.key_event.class, "<init>", "(II)V");
+
+	handle_cache.drawable.class = _REF((*env)->FindClass(env, "android/graphics/drawable/Drawable"));
+	handle_cache.drawable.draw = _METHOD(handle_cache.drawable.class, "draw", "(Landroid/graphics/Canvas;)V");
+	handle_cache.drawable.setBounds = _METHOD(handle_cache.drawable.class, "setBounds", "(IIII)V");
 }
 
 void extract_from_apk(const char *path, const char *target) {

src/api-impl-jni/util.h

@@ -100,6 +100,11 @@ struct handle_cache {
 		jclass class;
 		jmethodID constructor;
 	} key_event;
+	struct {
+		jclass class;
+		jmethodID draw;
+		jmethodID setBounds;
+	} drawable;
 };
 
 extern struct handle_cache handle_cache;

src/api-impl/android/graphics/Canvas.java

@@ -81,7 +81,7 @@ public class Canvas {
 	 * @param px The x-coord for the pivot point (unchanged by the rotation)
 	 * @param py The y-coord for the pivot point (unchanged by the rotation)
 	 */
-	public final void rotate(float degrees, float px, float py) {
+	public void rotate(float degrees, float px, float py) {
 		native_rotate_and_translate(skia_canvas, widget, degrees, px, py);
 	}
 	// ---

src/api-impl/android/graphics/GskCanvas.java

@@ -0,0 +1,74 @@
+package android.graphics;
+
+/**
+ * GskCanvas:
+ *   - implements Canvas for onscreen rendering inside GTKs snapshot function
+ */
+public class GskCanvas extends Canvas {
+	private long snapshot;
+
+	public GskCanvas(long snapshot) {
+		System.out.println("GskCanvas(" + snapshot + ")");
+		this.snapshot = snapshot;
+	}
+
+	@Override
+	public int save() {
+		System.out.println("GskCanvas.save()");
+		return -1;
+	}
+
+	@Override
+	public void restore() {
+		System.out.println("GskCanvas.restore()");
+	}
+
+	@Override
+	public void translate(float dx, float dy) {
+		System.out.println("GskCanvas.translate(" + dx + ", " + dy + ")");
+	}
+
+	@Override
+	public void rotate(float degrees) {
+		System.out.println("GskCanvas.rotate(" + degrees + ")");
+	}
+
+	@Override
+	public void drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint) {
+		native_drawBitmap(snapshot, bitmap.pixbuf, dst.left, dst.top, dst.width(), dst.height());
+	}
+
+	@Override
+	public void drawPath(Path path, Paint paint) {
+		System.out.println("GskCanvas.drawPath(" + path + ", " + paint + ")");
+	}
+
+	@Override
+	public void drawRect(float left, float top, float right, float bottom, Paint paint) {
+		System.out.println("GskCanvas.drawRect(" + left + ", " + top + ", " + right + ", " + bottom + ", " + paint + ")");
+	}
+
+	@Override
+	public void rotate(float degrees, float px, float py) {
+		System.out.println("GskCanvas.rotate(" + degrees + ", " + px + ", " + py + ")");
+	}
+
+	@Override
+	public void drawText(String text, float x, float y, Paint paint) {
+		System.out.println("GskCanvas.drawText(" + text + ", " + x + ", " + y + ", " + paint + ")");
+	}
+
+	@Override
+	public void drawLine(float startX, float startY, float stopX, float stopY, Paint paint) {
+		System.out.println("GskCanvas.drawLine(" + startX + ", " + startY + ", " + stopX + ", " + stopY + ", " + paint + ")");
+	}
+
+	@Override
+	public void drawBitmap(Bitmap bitmap, float left, float top, Paint paint) {
+		Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
+		Rect dst = new Rect((int)left, (int)top, (int)left + bitmap.getWidth(), (int)top + bitmap.getHeight());
+		drawBitmap(bitmap, src, dst, paint);
+	}
+
+	protected native void native_drawBitmap(long snapshot, long pixbuf, int x, int y, int width, int height);
+}

src/api-impl/android/graphics/drawable/Drawable.java

@@ -28,7 +28,9 @@ public class Drawable {
 	private int[] mStateSet = new int[0];
 	public long paintable;
 
-	public Drawable() {}
+	public Drawable() {
+		this.paintable = native_constructor();
+	}
 
 	public Drawable(long paintable) {
 		this.paintable = paintable;
@@ -180,4 +182,5 @@ public class Drawable {
 	}
 
 	protected static native long native_paintable_from_path(String path);
+	protected native long native_constructor();
 }

src/api-impl/android/graphics/drawable/GradientDrawable.java

@@ -1,15 +1,7 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
-
 public class GradientDrawable extends Drawable {
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
-
 	public void setColor(int color) {}
 
 	public void setCornerRadius(float cornerRadius) {}

src/api-impl/android/graphics/drawable/InsetDrawable.java

@@ -1,6 +1,5 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
 import android.graphics.Rect;
 
 public class InsetDrawable extends Drawable {
@@ -9,12 +8,6 @@ public class InsetDrawable extends Drawable {
 		super();
 	}
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
-
 	public boolean getPadding(Rect padding) { return false; }
 	
 }

src/api-impl/android/graphics/drawable/RippleDrawable.java

@@ -1,15 +1,9 @@
 package android.graphics.drawable;
 
 import android.content.res.ColorStateList;
-import android.graphics.Canvas;
 
 public class RippleDrawable extends Drawable {
 
 	public RippleDrawable(ColorStateList colorStateList, Drawable drawable, Drawable drawable2) {}
 
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
 }

src/api-impl/android/graphics/drawable/ShapeDrawable.java

@@ -1,6 +1,5 @@
 package android.graphics.drawable;
 
-import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.drawable.shapes.Shape;
 
@@ -9,11 +8,5 @@ public class ShapeDrawable extends Drawable {
 	public ShapeDrawable(Shape shape) {}
 
 	public Paint getPaint() {return new Paint();}
-
-	@Override
-	public void draw(Canvas canvas) {
-		// TODO Auto-generated method stub
-		throw new UnsupportedOperationException("Unimplemented method 'draw'");
-	}
 	
 }

src/api-impl/meson.build

@@ -161,6 +161,7 @@ hax_jar = jar('hax', [
               	'android/graphics/Canvas.java',
               	'android/graphics/Color.java',
               	'android/graphics/ColorFilter.java',
+              	'android/graphics/GskCanvas.java',
               	'android/graphics/Matrix.java',
               	'android/graphics/Paint.java',
               	'android/graphics/Path.java',