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Commit 3083c3c9 authored by Lucas Crowthers's avatar Lucas Crowthers Committed by Gerrit Code Review
Browse files

core/jni/android/graphics: Cache copy of pre-scaled Bitmaps 

Caching some pre-scaled Bitmap objects allows for optimizing later
scaling operations to reduce memory pressure.

CRs-fixed: 451681

Change-Id: Id4341e75911074ff9f565b2d386ccad8f3a223e8
parent c9b0de8a

core/jni/android/graphics/BitmapFactory.cpp

+11 −0
Original line number Diff line number Diff line
@@ -354,6 +354,17 @@ static jobject doDecode(JNIEnv* env, SkStream* stream, jobject padding, 
        SkCanvas canvas(*bitmap);

        canvas.scale(sx, sy);

        canvas.drawBitmap(*decoded, 0.0f, 0.0f, &paint);



        // Save off the unscaled version of bitmap to be used in later

        // transformations if it would reduce memory pressure. Only do

        // so if it is being upscaled more than 50%, is bigger than

        // 256x256, and not too big to be keeping a copy of (<1MB).

        const int numUnscaledPixels = decoded->width() * decoded->height();

        if (sx > 1.5 && numUnscaledPixels > 65536 && numUnscaledPixels < 262144) {

            bitmap->setUnscaledBitmap(decoded);

            adb2.detach(); //responsibility for freeing decoded's memory is

                           //transferred to bitmap's destructor

        }

    }



    if (padding) {

core/jni/android/graphics/Canvas.cpp

+20 −3
Original line number Diff line number Diff line
@@ -493,6 +493,7 @@ public: 
                        jobject srcIRect, const SkRect& dst, SkPaint* paint,

                        jint screenDensity, jint bitmapDensity) {

        SkIRect    src, *srcPtr = NULL;

        SkPaint    filteredPaint;



        if (NULL != srcIRect) {

            GraphicsJNI::jrect_to_irect(env, srcIRect, &src);
@@ -500,12 +501,28 @@ public: 
        }



        if (screenDensity != 0 && screenDensity != bitmapDensity) {

            SkPaint filteredPaint;

            if (paint) {

                filteredPaint = *paint;

            }

            filteredPaint.setFilterBitmap(true);

            canvas->drawBitmapRect(*bitmap, srcPtr, dst, &filteredPaint);

            paint = &filteredPaint;

        }



        //If we're doing downscaling and we have an unscaled bitmap, convert

        //this to an upscaling operation, or at least less of a downscale

        SkBitmap*  unscaled = bitmap->unscaledBitmap();

        if (NULL != srcPtr && NULL != unscaled) {

            //use new bitmap and adapt the coordinates of the src rect to this new bitmap

            SkScalar   dx, dy;

            SkRect     srcF;

            dx = SkScalarDiv(SkIntToScalar(unscaled->width()), SkIntToScalar(bitmap->width()));

            dy = SkScalarDiv(SkIntToScalar(unscaled->height()), SkIntToScalar(bitmap->height()));

            srcF.set(SkScalarMul(SkIntToScalar(src.left()), dx),

                SkScalarMul(SkIntToScalar(src.top()), dy),

                SkScalarMul(SkIntToScalar(src.right()), dx),

                SkScalarMul(SkIntToScalar(src.bottom()), dy));



            canvas->drawBitmapScalarRect(*unscaled, &srcF, dst, paint);

        } else {

            canvas->drawBitmapRect(*bitmap, srcPtr, dst, paint);

        }