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Commit 7aedf6f0 authored by Stan Iliev's avatar Stan Iliev
Browse files

Improve nine patch scaling 

Apply separate coefficient for X and Y, when scaling nine patch
lattice dividers. This is reducing rounding error and fixing
a nine patch issue in Clock app alarm background.
There are other issues in nine patch scaling (see ag/3378768).

Test: Ran clock app
Bug: 70353853
Change-Id: Ibbbfddc47767fb3314cdb88820e520b3f472e727
parent 1824f66c

core/jni/android/graphics/BitmapFactory.cpp

+10 −10
Original line number Diff line number Diff line
@@ -385,10 +385,18 @@ static jobject doDecode(JNIEnv* env, std::unique_ptr<SkStreamRewindable> stream, 
            return nullObjectReturn("codec->getAndroidPixels() failed.");

    }



    // This is weird so let me explain: we could use the scale parameter

    // directly, but for historical reasons this is how the corresponding

    // Dalvik code has always behaved. We simply recreate the behavior here.

    // The result is slightly different from simply using scale because of

    // the 0.5f rounding bias applied when computing the target image size

    const float scaleX = scaledWidth / float(decodingBitmap.width());

    const float scaleY = scaledHeight / float(decodingBitmap.height());



    jbyteArray ninePatchChunk = NULL;

    if (peeker.mPatch != NULL) {

        if (willScale) {

            peeker.scale(scale, scale, scaledWidth, scaledHeight);

            peeker.scale(scaleX, scaleY, scaledWidth, scaledHeight);

        }



        size_t ninePatchArraySize = peeker.mPatch->serializedSize();
@@ -419,14 +427,6 @@ static jobject doDecode(JNIEnv* env, std::unique_ptr<SkStreamRewindable> stream, 


    SkBitmap outputBitmap;

    if (willScale) {

        // This is weird so let me explain: we could use the scale parameter

        // directly, but for historical reasons this is how the corresponding

        // Dalvik code has always behaved. We simply recreate the behavior here.

        // The result is slightly different from simply using scale because of

        // the 0.5f rounding bias applied when computing the target image size

        const float sx = scaledWidth / float(decodingBitmap.width());

        const float sy = scaledHeight / float(decodingBitmap.height());



        // Set the allocator for the outputBitmap.

        SkBitmap::Allocator* outputAllocator;

        if (javaBitmap != nullptr) {
@@ -456,7 +456,7 @@ static jobject doDecode(JNIEnv* env, std::unique_ptr<SkStreamRewindable> stream, 
        paint.setFilterQuality(kLow_SkFilterQuality); // bilinear filtering



        SkCanvas canvas(outputBitmap, SkCanvas::ColorBehavior::kLegacy);

        canvas.scale(sx, sy);

        canvas.scale(scaleX, scaleY);

        canvas.drawBitmap(decodingBitmap, 0.0f, 0.0f, &paint);

    } else {

        outputBitmap.swap(decodingBitmap);

core/jni/android/graphics/NinePatchPeeker.cpp

+11 −6
Original line number Diff line number Diff line
@@ -76,13 +76,18 @@ void NinePatchPeeker::scale(float scaleX, float scaleY, int scaledWidth, int sca 
    if (!mPatch) {

        return;

    }

    mPatch->paddingLeft   = int(mPatch->paddingLeft   * scaleX + 0.5f);

    mPatch->paddingTop    = int(mPatch->paddingTop    * scaleY + 0.5f);

    mPatch->paddingRight  = int(mPatch->paddingRight  * scaleX + 0.5f);

    mPatch->paddingBottom = int(mPatch->paddingBottom * scaleY + 0.5f);



    // The max value for the divRange is one pixel less than the actual max to ensure that the size

    // of the last div is not zero. A div of size 0 is considered invalid input and will not render.

    if (!SkScalarNearlyEqual(scaleX, 1.0f)) {

        mPatch->paddingLeft   = int(mPatch->paddingLeft   * scaleX + 0.5f);

        mPatch->paddingRight  = int(mPatch->paddingRight  * scaleX + 0.5f);

        scaleDivRange(mPatch->getXDivs(), mPatch->numXDivs, scaleX, scaledWidth - 1);

    }



    if (!SkScalarNearlyEqual(scaleY, 1.0f)) {

        mPatch->paddingTop    = int(mPatch->paddingTop    * scaleY + 0.5f);

        mPatch->paddingBottom = int(mPatch->paddingBottom * scaleY + 0.5f);

        scaleDivRange(mPatch->getYDivs(), mPatch->numYDivs, scaleY, scaledHeight - 1);

    }

}