start to remove lockPixels from bitmapshader

src/core/SkBitmapProcState.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkBitmapProcState.h"
 #include "SkColorPriv.h"
 #include "SkFilterProc.h"
 #include "SkPaint.h"
 #include "SkShader.h"   // for tilemodes
 #include "SkUtilsArm.h"
 #include "SkBitmapScaler.h"
 #include "SkMipMap.h"
+#include "SkPixelRef.h"
 #include "SkScaledImageCache.h"
 
 #if !SK_ARM_NEON_IS_NONE
 // These are defined in src/opts/SkBitmapProcState_arm_neon.cpp
 extern const SkBitmapProcState::SampleProc16 gSkBitmapProcStateSample16_neon[];
 extern const SkBitmapProcState::SampleProc32 gSkBitmapProcStateSample32_neon[];
 extern void  S16_D16_filter_DX_neon(const SkBitmapProcState&, const uint32_t*, int, uint16_t*);
 extern void  Clamp_S16_D16_filter_DX_shaderproc_neon(const SkBitmapProcState&, int, int, uint16_t*, int);
 extern void  Repeat_S16_D16_filter_DX_shaderproc_neon(const SkBitmapProcState&, int, int, uint16_t*, int);
 extern void  SI8_opaque_D32_filter_DX_neon(const SkBitmapProcState&, const uint32_t*, int, SkPMColor*);
@@ skipping 76 matching lines @@
     v2.fX = mat.getSkewX();
     v2.fY = mat.getScaleY();
 
     return SkMaxScalar(v1.lengthSqd(), v2.lengthSqd());
 }
 
 // TODO -- we may want to pass the clip into this function so we only scale
 // the portion of the image that we're going to need.  This will complicate
 // the interface to the cache, but might be well worth it.
 
-void SkBitmapProcState::possiblyScaleImage() {
+bool SkBitmapProcState::possiblyScaleImage() {
+    SkASSERT(NULL == fBitmap);
+    SkASSERT(NULL == fScaledCacheID);
 
     if (fFilterLevel <= SkPaint::kLow_FilterLevel) {
-        // none or low (bilerp) does not need to look any further
-        return;
+        return false;
     }
 
-    // STEP 1: Highest quality direct scale?
-
     // Check to see if the transformation matrix is simple, and if we're
     // doing high quality scaling.  If so, do the bitmap scale here and
     // remove the scaling component from the matrix.
 
     if (SkPaint::kHigh_FilterLevel == fFilterLevel &&
         fInvMatrix.getType() <= (SkMatrix::kScale_Mask | SkMatrix::kTranslate_Mask) &&
         fOrigBitmap.config() == SkBitmap::kARGB_8888_Config) {
 
         SkScalar invScaleX = fInvMatrix.getScaleX();
         SkScalar invScaleY = fInvMatrix.getScaleY();
 
-        SkASSERT(NULL == fScaledCacheID);
         fScaledCacheID = SkScaledImageCache::FindAndLock(fOrigBitmap,
                                                          invScaleX, invScaleY,
                                                          &fScaledBitmap);
         if (NULL == fScaledCacheID) {
             int dest_width  = SkScalarCeilToInt(fOrigBitmap.width() / invScaleX);
             int dest_height = SkScalarCeilToInt(fOrigBitmap.height() / invScaleY);
 
             // All the criteria are met; let's make a new bitmap.
 
             SkConvolutionProcs simd;
             sk_bzero(&simd, sizeof(simd));
             this->platformConvolutionProcs(&simd);
 
             if (!SkBitmapScaler::Resize(&fScaledBitmap,
                                         fOrigBitmap,
                                         SkBitmapScaler::RESIZE_BEST,
                                         dest_width,
                                         dest_height,
                                         simd)) {
                 // we failed to create fScaledBitmap, so just return and let
                 // the scanline proc handle it.
-                return;
+                return true;
 
             }
             fScaledCacheID = SkScaledImageCache::AddAndLock(fOrigBitmap,
                                                             invScaleX,
                                                             invScaleY,
                                                             fScaledBitmap);
         }
-        fScaledBitmap.lockPixels();
-
+        fScaledBitmap.lockPixels(); // wonder if Resize() should have locked this
         fBitmap = &fScaledBitmap;
 
         // set the inv matrix type to translate-only;
-
         fInvMatrix.setTranslate(fInvMatrix.getTranslateX() / fInvMatrix.getScaleX(),
                                 fInvMatrix.getTranslateY() / fInvMatrix.getScaleY());
 
         // no need for any further filtering; we just did it!
-
         fFilterLevel = SkPaint::kNone_FilterLevel;
-
-        return;
+        return true;
     }
 
     /*
-     *  If we get here, the caller has requested either Med or High filter-level

[scroggo, 2013/09/10 18:08:31]

Do these comments no longer apply?

-     *
      *  If High, then our special-case for scale-only did not take, and so we
      *  have to make a choice:
      *      1. fall back on mipmaps + bilerp
      *      2. fall back on scanline bicubic filter
      *  For now, we compute the "scale" value from the matrix, and have a
      *  threshold to decide when bicubic is better, and when mips are better.
      *  No doubt a fancier decision tree could be used uere.
      *
      *  If Medium, then we just try to build a mipmap and select a level,
      *  setting the filter-level to kLow to signal that we just need bilerp
      *  to process the selected level.
      */
 
     SkScalar scaleSqd = effective_matrix_scale_sqrd(fInvMatrix);
 
     if (SkPaint::kHigh_FilterLevel == fFilterLevel) {
         // Set the limit at 0.25 for the CTM... if the CTM is scaling smaller
         // than this, then the mipmaps quality may be greater (certainly faster)
         // so we only keep High quality if the scale is greater than this.
         //
         // Since we're dealing with the inverse, we compare against its inverse.
         const SkScalar bicubicLimit = SkFloatToScalar(4.0f);
         const SkScalar bicubicLimitSqd = bicubicLimit * bicubicLimit;
         if (scaleSqd < bicubicLimitSqd) {  // use bicubic scanline
-            return;
+            return false;
         }
 
         // else set the filter-level to Medium, since we're scaling down and
         // want to reqeust mipmaps
         fFilterLevel = SkPaint::kMedium_FilterLevel;
     }
 
     SkASSERT(SkPaint::kMedium_FilterLevel == fFilterLevel);
 
     /**
@@ skipping 24 matching lines @@
             SkMipMap::Level level;
             if (mip->extractLevel(levelScale, &level)) {
                 SkScalar invScaleFixup = level.fScale;
                 fInvMatrix.postScale(invScaleFixup, invScaleFixup);
 
                 fScaledBitmap.setConfig(fOrigBitmap.config(),
                                         level.fWidth, level.fHeight,
                                         level.fRowBytes);
                 fScaledBitmap.setPixels(level.fPixels);
                 fBitmap = &fScaledBitmap;
+                fFilterLevel = SkPaint::kLow_FilterLevel;
+                return true;
             }
         }
     }
 
-    /*
-     *  At this point, we may or may not have built a mipmap. Regardless, we
-     *  now fall back on Low so will bilerp whatever fBitmap now points at.
-     */
-    fFilterLevel = SkPaint::kLow_FilterLevel;

[scroggo, 2013/09/10 18:08:31]

This appears to be a change in behavior: if !mip || scaleSqd >= SK_Scalar1, we
no longer set fFilterLevel to SkPaint::kLow_FilterLevel. Is this intended?

+    return false;
+}
+
+static bool decodeInto(const SkBitmap& src, int pow2, SkBitmap* dst) {

[scroggo, 2013/09/10 18:08:31]

Style nit: decode_into

[reed1, 2013/09/10 20:28:11]

Done.

+    // new way to decodeInto...

[scroggo, 2013/09/10 18:08:31]

Should there be some more explicit comments, eg FIXME, in progress etc?

[reed1, 2013/09/10 20:28:11]

Done.

+    SkPixelRef* pr = src.pixelRef();
+    if (pr && pr->decodeInto(pow2, dst)) {
+        return true;
+    }
+
+    // olde school impl... ignores pow2
+    src.lockPixels();
+    if (!src.getPixels()) {
+        return false;
+    }
+    *dst = src;
+    dst->lockPixels();
+    src.unlockPixels();
+    return SkToBool(dst->getPixels());
+}
+
+bool SkBitmapProcState::lockBaseBitmap() {

[scroggo, 2013/09/10 18:08:31]

Will this function become more general to lock other versions besides the base
bitmap?

[reed1, 2013/09/10 20:28:11]

I think not. I think that functionality belongs in possiblyScaleBitmap, where we
worry about mipmaps etc.

+    fScaledCacheID = SkScaledImageCache::FindAndLock(fOrigBitmap,
+                                                     SK_Scalar1, SK_Scalar1,
+                                                     &fScaledBitmap);
+    if (NULL == fScaledCacheID) {
+        if (!decodeInto(fOrigBitmap, 0, &fScaledBitmap)) {
+            return false;
+        }
+
+        fScaledCacheID = SkScaledImageCache::AddAndLock(fOrigBitmap,
+                                                        SK_Scalar1, SK_Scalar1,
+                                                        fScaledBitmap);
+        if (!fScaledCacheID) {
+            fScaledBitmap.reset();
+            return false;
+        }
+    }
+
+    fScaledBitmap.lockPixels(); // just 'cause the cache made a copy :(
+    fBitmap = &fScaledBitmap;
+    return true;
 }
 
 void SkBitmapProcState::endContext() {
     SkDELETE(fBitmapFilter);
     fBitmapFilter = NULL;
     fScaledBitmap.reset();
 
     if (fScaledCacheID) {
         SkScaledImageCache::Unlock(fScaledCacheID);
         fScaledCacheID = NULL;
     }
 }
 
 SkBitmapProcState::~SkBitmapProcState() {
     if (fScaledCacheID) {
         SkScaledImageCache::Unlock(fScaledCacheID);
     }
     SkDELETE(fBitmapFilter);
 }
 
 bool SkBitmapProcState::chooseProcs(const SkMatrix& inv, const SkPaint& paint) {
-    if (fOrigBitmap.width() == 0 || fOrigBitmap.height() == 0) {
-        return false;
-    }
+    SkASSERT(fOrigBitmap.width() && fOrigBitmap.height());
 
-    fBitmap = &fOrigBitmap;
+    fBitmap = NULL;
     fInvMatrix = inv;
-
-    // initialize our filter quality to the one requested by the caller.
-    // We may downgrade it later if we determine that we either don't need
-    // or can't provide as high a quality filtering as the user requested.
-
     fFilterLevel = paint.getFilterLevel();
 
     // possiblyScaleImage will look to see if it can rescale the image as a
     // preprocess; either by scaling up to the target size, or by selecting
     // a nearby mipmap level.  If it does, it will adjust the working
     // matrix as well as the working bitmap.  It may also adjust the filter
     // quality to avoid re-filtering an already perfectly scaled image.
-
-    this->possiblyScaleImage();
+    if (!this->possiblyScaleImage()) {
+        if (!this->lockBaseBitmap()) {
+            return false;
+        }
+    }
+    
+    SkASSERT(fBitmap);
 
     bool trivialMatrix = (fInvMatrix.getType() & ~SkMatrix::kTranslate_Mask) == 0;
     bool clampClamp = SkShader::kClamp_TileMode == fTileModeX &&
                       SkShader::kClamp_TileMode == fTileModeY;
     
     if (!(clampClamp || trivialMatrix)) {
         fInvMatrix.postIDiv(fOrigBitmap.width(), fOrigBitmap.height());
     }
 
     // Now that all possible changes to the matrix have taken place, check
     // to see if we're really close to a no-scale matrix.  If so, explicitly
     // set it to be so.  Subsequent code may inspect this matrix to choose
     // a faster path in this case.
 
     // This code will only execute if the matrix has some scale component;
     // if it's already pure translate then we won't do this inversion.
 
     if (matrix_only_scale_translate(fInvMatrix)) {
         SkMatrix forward;
         if (fInvMatrix.invert(&forward)) {
             if (clampClamp ? just_trans_clamp(forward, *fBitmap)
                             : just_trans_general(forward)) {
                 SkScalar tx = -SkScalarRoundToScalar(forward.getTranslateX());
                 SkScalar ty = -SkScalarRoundToScalar(forward.getTranslateY());
                 fInvMatrix.setTranslate(tx, ty);
-
             }
         }
     }
 
     fInvProc        = fInvMatrix.getMapXYProc();
     fInvType        = fInvMatrix.getType();
     fInvSx          = SkScalarToFixed(fInvMatrix.getScaleX());
     fInvSxFractionalInt = SkScalarToFractionalInt(fInvMatrix.getScaleX());
     fInvKy          = SkScalarToFixed(fInvMatrix.getSkewY());
     fInvKyFractionalInt = SkScalarToFractionalInt(fInvMatrix.getSkewY());
@@ skipping 596 matching lines @@
     } else {
         size >>= 2;
     }
 
     if (fFilterLevel != SkPaint::kNone_FilterLevel) {
         size >>= 1;
     }
 
     return size;
 }