android/graphics/NinePatch.cpp

/*
**
** Copyright 2006, The Android Open Source Project
**
** 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.
*/

#define LOG_TAG "9patch"
#define LOG_NDEBUG 1

#include <androidfw/ResourceTypes.h>
#include <utils/Log.h>

#include <Caches.h>

#include "SkCanvas.h"
#include "SkRegion.h"
#include "GraphicsJNI.h"

#include "JNIHelp.h"

extern void NinePatch_Draw(SkCanvas* canvas, const SkRect& bounds, const SkBitmap& bitmap,
        const android::Res_png_9patch& chunk, const SkPaint* paint, SkRegion** outRegion);

using namespace android;

/**
 * IMPORTANT NOTE: 9patch chunks can be manipuated either as an array of bytes
 * or as a Res_png_9patch instance. It is important to note that the size of the
 * array required to hold a 9patch chunk is greater than sizeof(Res_png_9patch).
 * The code below manipulates chunks as Res_png_9patch* types to draw and as
 * int8_t* to allocate and free the backing storage.
 */

class SkNinePatchGlue {
public:
    static jboolean isNinePatchChunk(JNIEnv* env, jobject, jbyteArray obj) {
        if (NULL == obj) {
            return false;
        }
        if (env->GetArrayLength(obj) < (int)sizeof(Res_png_9patch)) {
            return false;
        }
        const jbyte* array = env->GetByteArrayElements(obj, 0);
        if (array != NULL) {
            const Res_png_9patch* chunk = reinterpret_cast<const Res_png_9patch*>(array);
            int8_t wasDeserialized = chunk->wasDeserialized;
            env->ReleaseByteArrayElements(obj, const_cast<jbyte*>(array), JNI_ABORT);
            return wasDeserialized != -1;
        }
        return false;
    }

    static int8_t* validateNinePatchChunk(JNIEnv* env, jobject, jint, jbyteArray obj) {
        size_t chunkSize = env->GetArrayLength(obj);
        if (chunkSize < (int) (sizeof(Res_png_9patch))) {
            jniThrowRuntimeException(env, "Array too small for chunk.");
            return NULL;
        }

        int8_t* storage = new int8_t[chunkSize];
        // This call copies the content of the jbyteArray
        env->GetByteArrayRegion(obj, 0, chunkSize, reinterpret_cast<jbyte*>(storage));
        // Deserialize in place, return the array we just allocated
        return (int8_t*) Res_png_9patch::deserialize(storage);
    }

    static void finalize(JNIEnv* env, jobject, int8_t* patch) {
#ifdef USE_OPENGL_RENDERER
        if (android::uirenderer::Caches::hasInstance()) {
            Res_png_9patch* p = (Res_png_9patch*) patch;
            android::uirenderer::Caches::getInstance().resourceCache.destructor(p);
            return;
        }
#endif // USE_OPENGL_RENDERER
        delete[] patch;
    }

    static void draw(JNIEnv* env, SkCanvas* canvas, SkRect& bounds, const SkBitmap* bitmap,
            Res_png_9patch* chunk, const SkPaint* paint, jint destDensity, jint srcDensity) {
        if (destDensity == srcDensity || destDensity == 0 || srcDensity == 0) {
            ALOGV("Drawing unscaled 9-patch: (%g,%g)-(%g,%g)",
                    SkScalarToFloat(bounds.fLeft), SkScalarToFloat(bounds.fTop),
                    SkScalarToFloat(bounds.fRight), SkScalarToFloat(bounds.fBottom));
            NinePatch_Draw(canvas, bounds, *bitmap, *chunk, paint, NULL);
        } else {
            canvas->save();

            SkScalar scale = SkFloatToScalar(destDensity / (float)srcDensity);
            canvas->translate(bounds.fLeft, bounds.fTop);
            canvas->scale(scale, scale);

            bounds.fRight = SkScalarDiv(bounds.fRight-bounds.fLeft, scale);
            bounds.fBottom = SkScalarDiv(bounds.fBottom-bounds.fTop, scale);
            bounds.fLeft = bounds.fTop = 0;

            ALOGV("Drawing scaled 9-patch: (%g,%g)-(%g,%g) srcDensity=%d destDensity=%d",
                    SkScalarToFloat(bounds.fLeft), SkScalarToFloat(bounds.fTop),
                    SkScalarToFloat(bounds.fRight), SkScalarToFloat(bounds.fBottom),
                    srcDensity, destDensity);

            NinePatch_Draw(canvas, bounds, *bitmap, *chunk, paint, NULL);

            canvas->restore();
        }
    }

    static void drawF(JNIEnv* env, jobject, SkCanvas* canvas, jobject boundsRectF,
            const SkBitmap* bitmap, Res_png_9patch* chunk, const SkPaint* paint,
            jint destDensity, jint srcDensity) {
        SkASSERT(canvas);
        SkASSERT(boundsRectF);
        SkASSERT(bitmap);
        SkASSERT(chunk);
        // paint is optional

        SkRect bounds;
        GraphicsJNI::jrectf_to_rect(env, boundsRectF, &bounds);

        draw(env, canvas, bounds, bitmap, chunk, paint, destDensity, srcDensity);
    }

    static void drawI(JNIEnv* env, jobject, SkCanvas* canvas, jobject boundsRect,
            const SkBitmap* bitmap, Res_png_9patch* chunk, const SkPaint* paint,
            jint destDensity, jint srcDensity) {
        SkASSERT(canvas);
        SkASSERT(boundsRect);
        SkASSERT(bitmap);
        SkASSERT(chunk);
        // paint is optional

        SkRect bounds;
        GraphicsJNI::jrect_to_rect(env, boundsRect, &bounds);
        draw(env, canvas, bounds, bitmap, chunk, paint, destDensity, srcDensity);
    }

    static jint getTransparentRegion(JNIEnv* env, jobject, const SkBitmap* bitmap,
            Res_png_9patch* chunk, jobject boundsRect) {
        SkASSERT(bitmap);
        SkASSERT(chunk);
        SkASSERT(boundsRect);

        SkRect bounds;
        GraphicsJNI::jrect_to_rect(env, boundsRect, &bounds);

        SkRegion* region = NULL;
        NinePatch_Draw(NULL, bounds, *bitmap, *chunk, NULL, &region);

        return (jint) region;
    }

};

/////////////////////////////////////////////////////////////////////////////////////////

#include <android_runtime/AndroidRuntime.h>

static JNINativeMethod gNinePatchMethods[] = {
    { "isNinePatchChunk", "([B)Z",                        (void*) SkNinePatchGlue::isNinePatchChunk },
    { "validateNinePatchChunk", "(I[B)I",                 (void*) SkNinePatchGlue::validateNinePatchChunk },
    { "nativeFinalize", "(I)V",                           (void*) SkNinePatchGlue::finalize },
    { "nativeDraw", "(ILandroid/graphics/RectF;IIIII)V",  (void*) SkNinePatchGlue::drawF },
    { "nativeDraw", "(ILandroid/graphics/Rect;IIIII)V",   (void*) SkNinePatchGlue::drawI },
    { "nativeGetTransparentRegion", "(IILandroid/graphics/Rect;)I",
                                                          (void*) SkNinePatchGlue::getTransparentRegion }
};

int register_android_graphics_NinePatch(JNIEnv* env) {
    return android::AndroidRuntime::registerNativeMethods(env,
            "android/graphics/NinePatch", gNinePatchMethods, SK_ARRAY_COUNT(gNinePatchMethods));
}