do not cache SkBitmap in SkiaSalBitmap

It doesn't make much sense anymore to keep it around, it's now used
only by GetAsSkImage(), which is only called from GetSkImage() and
GetSkAlphaImage(), and it's unlikely one SkiaSalBitmap would
be used both as a bitmap and an alpha mask.
In Vulkan mode this should save the memory (in raster mode the memory
is shared by the SkImage).

Change-Id: I5818a462aca85906f2e82cd951b6241d954723c6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/94228
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

2 files changed, 16 insertions, 33 deletions

diff --git a/vcl/inc/skia/salbmp.hxx b/vcl/inc/skia/salbmp.hxx
index d13e765d63cd..7eb2a8eb72a6 100644
--- a/vcl/inc/skia/salbmp.hxx
+++ b/vcl/inc/skia/salbmp.hxx
@@ -71,8 +71,7 @@ public:
 #endif
 
 private:
-    // Reset the cached images allocated in GetSkImage()/GetAlphaSkImage(),
-    // and also the SkBitmap allocated in GetAsSkBitmap().
+    // Reset the cached images allocated in GetSkImage()/GetAlphaSkImage().
     void ResetCachedData();
     // Sets the data only as SkImage (will be converted as needed).
     void ResetToSkImage(sk_sp<SkImage> image);
@@ -97,10 +96,9 @@ private:
     friend inline std::basic_ostream<charT, traits>&
     operator<<(std::basic_ostream<charT, traits>& stream, const SkiaSalBitmap* bitmap)
     {
-        // B - has SkBitmap, I/i - has SkImage (on GPU/CPU),
+        // I/i - has SkImage (on GPU/CPU),
         // A/a - has alpha SkImage (on GPU/CPU)
         return stream << static_cast<const void*>(bitmap) << " " << bitmap->GetSize() << "/"
-                      << bitmap->mBitCount << (!bitmap->mBitmap.isNull() ? "B" : "")
                       << (bitmap->mImage ? (bitmap->mImage->isTextureBacked() ? "I" : "i") : "")
                       << (bitmap->mAlphaImage ? (bitmap->mAlphaImage->isTextureBacked() ? "A" : "a")
                                               : "");
@@ -119,7 +117,6 @@ private:
     // mBuffer must be filled from it on demand if necessary by EnsureBitmapData().
     boost::shared_ptr<sal_uInt8[]> mBuffer;
     int mScanlineSize; // size of one row in mBuffer
-    SkBitmap mBitmap; // cached mBuffer, if needed
     sk_sp<SkImage> mImage; // possibly GPU-backed
     sk_sp<SkImage> mAlphaImage; // cached contents as alpha image, possibly GPU-backed
     // Actual scaling triggered by scale() is done on-demand. This is the size of the pixel
diff --git a/vcl/skia/salbmp.cxx b/vcl/skia/salbmp.cxx
index d48e67c4e904..1bf0f77bfc2a 100644
--- a/vcl/skia/salbmp.cxx
+++ b/vcl/skia/salbmp.cxx
@@ -93,7 +93,6 @@ bool SkiaSalBitmap::Create(const Size& rSize, sal_uInt16 nBitCount, const Bitmap
 
 bool SkiaSalBitmap::CreateBitmapData()
 {
-    assert(mBitmap.isNull());
     assert(!mBuffer);
     // The pixels could be stored in SkBitmap, but Skia only supports 8bit gray, 16bit and 32bit formats
     // (e.g. 24bpp is actually stored as 32bpp). But some of our code accessing the bitmap assumes that
@@ -140,9 +139,6 @@ bool SkiaSalBitmap::Create(const SalBitmap& rSalBmp, SalGraphics* pGraphics)
 bool SkiaSalBitmap::Create(const SalBitmap& rSalBmp, sal_uInt16 nNewBitCount)
 {
     const SkiaSalBitmap& src = static_cast<const SkiaSalBitmap&>(rSalBmp);
-    mBitmap = src.mBitmap;
-    // SkBitmap shares pixels on copy.
-    assert(mBitmap.getPixels() == src.mBitmap.getPixels());
     mImage = src.mImage;
     mAlphaImage = src.mAlphaImage;
     mBuffer = src.mBuffer;
@@ -389,7 +385,7 @@ bool SkiaSalBitmap::InterpretAs8Bit()
     // the content as an alpha channel. This is often used
     // by the horrible separate-alpha-outdev hack, where the bitmap comes
     // from SkiaSalGraphicsImpl::GetBitmap(), so only mImage is set,
-    // and that is followed by a later call to GetAlphaSkBitmap().
+    // and that is followed by a later call to GetAlphaSkImage().
     // Avoid the costly SkImage->buffer->SkImage conversion and simply
     // just treat the SkImage as being for 8bit bitmap. EnsureBitmapData()
     // will do the conversion if needed, but the normal case will be
@@ -410,8 +406,6 @@ SkBitmap SkiaSalBitmap::GetAsSkBitmap() const
 #ifdef DBG_UTIL
     assert(mWriteAccessCount == 0);
 #endif
-    if (!mBitmap.isNull())
-        return mBitmap;
     EnsureBitmapData();
     assert(mSize == mPixelsSize); // data has already been scaled if needed
     SkiaZone zone;
@@ -479,8 +473,7 @@ SkBitmap SkiaSalBitmap::GetAsSkBitmap() const
             bitmap.setImmutable();
         }
     }
-    const_cast<SkBitmap&>(mBitmap) = bitmap;
-    return mBitmap;
+    return bitmap;
 }
 
 const sk_sp<SkImage>& SkiaSalBitmap::GetSkImage() const
@@ -491,7 +484,7 @@ const sk_sp<SkImage>& SkiaSalBitmap::GetSkImage() const
     if (mPixelsSize != mSize && !mImage
         && SkiaHelper::renderMethodToUse() != SkiaHelper::RenderRaster)
     {
-        // The bitmap has a pending scaling, but no image. This function would below call GetSkBitmap(),
+        // The bitmap has a pending scaling, but no image. This function would below call GetAsSkBitmap(),
         // which would do CPU-based pixel scaling, and then it would get converted to an image.
         // Be more efficient, first convert to an image and then the block below will scale on the GPU.
         SAL_INFO("vcl.skia.trace", "getskimage(" << this << "): shortcut image scaling "
@@ -576,7 +569,7 @@ const sk_sp<SkImage>& SkiaSalBitmap::GetAlphaSkImage() const
                                                           << "->" << mSize << ":"
                                                           << static_cast<int>(mScaleQuality));
         else
-            SAL_INFO("vcl.skia.trace", "getalphaskbitmap(" << this << ") from image");
+            SAL_INFO("vcl.skia.trace", "getalphaskimage(" << this << ") from image");
         SkiaSalBitmap* thisPtr = const_cast<SkiaSalBitmap*>(this);
         thisPtr->mAlphaImage = surface->makeImageSnapshot();
         return mAlphaImage;
@@ -619,7 +612,7 @@ const sk_sp<SkImage>& SkiaSalBitmap::GetAlphaSkImage() const
         SkiaSalBitmap* thisPtr = const_cast<SkiaSalBitmap*>(this);
         thisPtr->mAlphaImage = surface->makeImageSnapshot();
     }
-    SAL_INFO("vcl.skia.trace", "getalphaskbitmap(" << this << ")");
+    SAL_INFO("vcl.skia.trace", "getalphaskimage(" << this << ")");
     return mAlphaImage;
 }
 
@@ -674,15 +667,15 @@ void SkiaSalBitmap::EnsureBitmapData()
     SkiaZone zone;
     if (!CreateBitmapData())
         abort();
-    assert(mBitmap.isNull());
     SkAlphaType alphaType = kUnpremul_SkAlphaType;
 #if SKIA_USE_BITMAP32
     if (mBitCount == 32)
         alphaType = kPremul_SkAlphaType;
 #endif
-    if (!mBitmap.tryAllocPixels(SkImageInfo::MakeS32(mSize.Width(), mSize.Height(), alphaType)))
+    SkBitmap bitmap;
+    if (!bitmap.tryAllocPixels(SkImageInfo::MakeS32(mSize.Width(), mSize.Height(), alphaType)))
         abort();
-    SkCanvas canvas(mBitmap);
+    SkCanvas canvas(bitmap);
     SkPaint paint;
     paint.setBlendMode(SkBlendMode::kSrc); // set as is, including alpha
     if (mSize != mPixelsSize) // pending scaling?
@@ -697,19 +690,19 @@ void SkiaSalBitmap::EnsureBitmapData()
         mPixelsSize = mSize;
         mScaleQuality = kNone_SkFilterQuality;
         // Information about the pending scaling has been discarded, so make sure we do not
-        // keep around any cached images would still need scaling.
+        // keep around any cached images that would still need scaling.
         ResetCachedDataBySize();
     }
     else
         canvas.drawImage(mImage, 0, 0, &paint);
     canvas.flush();
-    mBitmap.setImmutable();
+    bitmap.setImmutable();
     assert(mBuffer != nullptr);
     if (mBitCount == 32)
     {
         for (long y = 0; y < mSize.Height(); ++y)
         {
-            const uint8_t* src = static_cast<uint8_t*>(mBitmap.getAddr(0, y));
+            const uint8_t* src = static_cast<uint8_t*>(bitmap.getAddr(0, y));
             sal_uInt8* dest = mBuffer.get() + mScanlineSize * y;
             memcpy(dest, src, mScanlineSize);
         }
@@ -718,7 +711,7 @@ void SkiaSalBitmap::EnsureBitmapData()
     {
         for (long y = 0; y < mSize.Height(); ++y)
         {
-            const uint8_t* src = static_cast<uint8_t*>(mBitmap.getAddr(0, y));
+            const uint8_t* src = static_cast<uint8_t*>(bitmap.getAddr(0, y));
             sal_uInt8* dest = mBuffer.get() + mScanlineSize * y;
             for (long x = 0; x < mSize.Width(); ++x)
             {
@@ -733,7 +726,7 @@ void SkiaSalBitmap::EnsureBitmapData()
     {
         for (long y = 0; y < mSize.Height(); ++y)
         {
-            const uint8_t* src = static_cast<uint8_t*>(mBitmap.getAddr(0, y));
+            const uint8_t* src = static_cast<uint8_t*>(bitmap.getAddr(0, y));
             sal_uInt8* dest = mBuffer.get() + mScanlineSize * y;
             // no actual data conversion, use one color channel as the gray value
             for (long x = 0; x < mSize.Width(); ++x)
@@ -746,7 +739,7 @@ void SkiaSalBitmap::EnsureBitmapData()
             = vcl::ScanlineWriter::Create(mBitCount, mPalette);
         for (long y = 0; y < mSize.Height(); ++y)
         {
-            const uint8_t* src = static_cast<uint8_t*>(mBitmap.getAddr(0, y));
+            const uint8_t* src = static_cast<uint8_t*>(bitmap.getAddr(0, y));
             sal_uInt8* dest = mBuffer.get() + mScanlineSize * y;
             pWriter->nextLine(dest);
             for (long x = 0; x < mSize.Width(); ++x)
@@ -766,7 +759,6 @@ void SkiaSalBitmap::EnsureBitmapData()
 void SkiaSalBitmap::EnsureBitmapUniqueData()
 {
     EnsureBitmapData();
-    mBitmap.reset(); // just reset, this function is called before modifying mBuffer
     if (mBuffer.use_count() > 1)
     {
         sal_uInt32 allocate = mScanlineSize * mSize.Height();
@@ -786,7 +778,6 @@ void SkiaSalBitmap::ResetCachedData()
     // There may be a case when only mImage is set and CreatBitmapData() will create
     // mBuffer from it if needed, in that case ResetToSkImage() should be used.
     assert(mBuffer.get() || !mImage);
-    mBitmap.reset();
     mImage.reset();
     mAlphaImage.reset();
 }
@@ -795,7 +786,6 @@ void SkiaSalBitmap::ResetToSkImage(sk_sp<SkImage> image)
 {
     SkiaZone zone;
     mBuffer.reset();
-    mBitmap.reset();
     mImage = image;
     mAlphaImage.reset();
 }
@@ -803,8 +793,6 @@ void SkiaSalBitmap::ResetToSkImage(sk_sp<SkImage> image)
 void SkiaSalBitmap::ResetCachedDataBySize()
 {
     SkiaZone zone;
-    assert(!mBitmap.isNull());
-    assert(mBitmap.width() == mSize.getWidth() && mBitmap.height() == mSize.getHeight());
     assert(mSize == mPixelsSize);
     if (mImage && (mImage->width() != mSize.getWidth() || mImage->height() != mSize.getHeight()))
         mImage.reset();
@@ -818,7 +806,6 @@ void SkiaSalBitmap::dump(const char* file) const
 {
     sk_sp<SkImage> saveImage = mImage;
     sk_sp<SkImage> saveAlphaImage = mAlphaImage;
-    SkBitmap saveBitmap = mBitmap;
     bool resetBuffer = !mBuffer;
     int saveWriteAccessCount = mWriteAccessCount;
     Size savePrescaleSize = mPixelsSize;
@@ -827,7 +814,6 @@ void SkiaSalBitmap::dump(const char* file) const
     thisPtr->mWriteAccessCount = 0;
     SkiaHelper::dump(GetSkImage(), file);
     // restore old state, so that debugging doesn't affect it
-    thisPtr->mBitmap = saveBitmap;
     if (resetBuffer)
         thisPtr->mBuffer.reset();
     thisPtr->mImage = saveImage;