Separate out natively-texture image/bmp draws from cached-as-texture image/bmp draws

src/gpu/GrTextureParamsAdjuster.cpp

Index: src/gpu/GrTextureParamsAdjuster.cpp
diff --git a/src/gpu/GrTextureParamsAdjuster.cpp b/src/gpu/GrTextureParamsAdjuster.cpp
index 579cf96ef36d30823a70b491cc0015e6813be116..b98a126971de0836d666226a184179d50588632c 100644
--- a/src/gpu/GrTextureParamsAdjuster.cpp
+++ b/src/gpu/GrTextureParamsAdjuster.cpp
@@ -19,6 +19,7 @@
 #include "SkCanvas.h"
 #include "SkGr.h"
 #include "SkGrPriv.h"
+#include "effects/GrBicubicEffect.h"
 #include "effects/GrTextureDomain.h"
 
 typedef GrTextureProducer::CopyParams CopyParams;
@@ -131,7 +132,7 @@ GrTexture* GrTextureAdjuster::refTextureSafeForParams(const GrTextureParams& par
     GrTexture* texture = this->originalTexture();
     GrContext* context = texture->getContext();
     CopyParams copyParams;
-    const SkIRect* contentArea = this->contentArea();
+    const SkIRect* contentArea = this->contentAreaOrNull();
 
     if (contentArea && GrTextureParams::kMipMap_FilterMode == params.filterMode()) {
         // If we generate a MIP chain for texture it will read pixel values from outside the content
@@ -171,6 +172,211 @@ GrTexture* GrTextureAdjuster::refTextureSafeForParams(const GrTextureParams& par
     return result;
 }
 
+enum DomainMode {
+    kNoDomain_DomainMode,
+    kDomain_DomainMode,
+    kTightCopy_DomainMode
+};
+
+/** Determines whether a texture domain is necessary and if so what domain to use. There are two
+ *  rectangles to consider:
+ *  - The first is the content area specified by the texture adjuster. We can *never* allow
+ *    filtering to cause bleed of pixels outside this rectangle.
+ *  - The second rectangle is the constraint rectangle, which is known to be contained by the
+ *    content area. The filterConstraint specifies whether we are allowed to bleed across this
+ *    rect.
+ *
+ *  We want to avoid using a domain if possible. We consider the above rectangles, the filter type,
+ *  and whether the coords generated by the draw would all fall within the constraint rect. If the
+ *  latter is true we only need to consider whether the filter would extend beyond the rects.
+ */
+static DomainMode determine_domain_mode(
+                                    const SkRect& constraintRect,
+                                    GrTextureAdjuster::FilterConstraint filterConstraint,
+                                    bool coordsLimitedToConstraintRect,
+                                    int texW, int texH,
+                                    const SkIRect* textureContentArea,
+                                    const GrTextureParams::FilterMode* filterModeOrNullForBicubic,
+                                    SkRect* domainRect) {
+
+    SkASSERT(SkRect::MakeIWH(texW, texH).contains(constraintRect));
+    // We only expect a content area rect if there is some non-content area.
+    SkASSERT(!textureContentArea ||
+             (!textureContentArea->contains(SkIRect::MakeWH(texW, texH)) &&
+              SkRect::Make(*textureContentArea).contains(constraintRect)));
+
+    SkRect textureBounds = SkRect::MakeIWH(texW, texH);
+    // If the src rectangle contains the whole texture then no need for a domain.
+    if (constraintRect.contains(textureBounds)) {
+        return kNoDomain_DomainMode;
+    }
+
+    bool restrictFilterToRect = (filterConstraint == GrTextureAdjuster::kYes_FilterConstraint);
+
+    // If we can filter outside the constraint rect, and there is no non-content area of the
+    // texture, and we aren't going to generate sample coords outside the constraint rect then we
+    // don't need a domain.
+    if (!restrictFilterToRect && !textureContentArea && coordsLimitedToConstraintRect) {
+        return kNoDomain_DomainMode;
+    }
+
+    // Get the domain inset based on sampling mode (or bail if mipped)
+    SkScalar filterHalfWidth = 0.f;
+    if (filterModeOrNullForBicubic) {
+        switch (*filterModeOrNullForBicubic) {
+            case GrTextureParams::kNone_FilterMode:
+                if (coordsLimitedToConstraintRect) {
+                    return kNoDomain_DomainMode;
+                } else {
+                    filterHalfWidth = 0.f;
+                }
+                break;
+            case GrTextureParams::kBilerp_FilterMode:
+                filterHalfWidth = .5f;
+                break;
+            case GrTextureParams::kMipMap_FilterMode:
+                // No domain can save use here.
+                return kTightCopy_DomainMode;
+        }
+    } else {
+        // bicubic does nearest filtering internally.
+        filterHalfWidth = 1.5f;
+    }
+
+    // Both bilerp and bicubic use bilinear filtering and so need to be clamped to the center
+    // of the edge texel. Pinning to the texel center has no impact on nearest mode and MIP-maps
+
+    static const SkScalar kDomainInset = 0.5f;
+    // Figure out the limits of pixels we're allowed to sample from.
+    // Unless we know the amount of outset and the texture matrix we have to conservatively enforce
+    // the domain.
+    if (restrictFilterToRect) {
+        domainRect->fLeft = constraintRect.fLeft + kDomainInset;
+        domainRect->fTop = constraintRect.fTop + kDomainInset;
+        domainRect->fRight = constraintRect.fRight - kDomainInset;
+        domainRect->fBottom = constraintRect.fBottom - kDomainInset;
+    } else if (textureContentArea) {
+        // If we got here then: there is a textureContentArea, the coords are limited to the
+        // constraint rect, and we're allowed to filter across the constraint rect boundary. So
+        // we check whether the filter would reach across the edge of the content area.
+        // We will only set the sides that are required.
+
+        domainRect->setLargest();
+        if (coordsLimitedToConstraintRect) {
+            // We may be able to use the fact that the texture coords are limited to the constraint
+            // rect in order to avoid having to add a domain.
+            bool needContentAreaConstraint = false;
+            if (textureContentArea->fLeft > 0 &&
+                textureContentArea->fLeft + filterHalfWidth > constraintRect.fLeft) {
+                domainRect->fLeft = textureContentArea->fLeft + kDomainInset;
+                needContentAreaConstraint = true;
+            }
+            if (textureContentArea->fTop > 0 &&
+                textureContentArea->fTop + filterHalfWidth > constraintRect.fTop) {
+                domainRect->fTop = textureContentArea->fTop + kDomainInset;
+                needContentAreaConstraint = true;
+            }
+            if (textureContentArea->fRight < texW &&
+                textureContentArea->fRight - filterHalfWidth < constraintRect.fRight) {
+                domainRect->fRight = textureContentArea->fRight - kDomainInset;
+                needContentAreaConstraint = true;
+            }
+            if (textureContentArea->fBottom < texH &&
+                textureContentArea->fBottom - filterHalfWidth < constraintRect.fBottom) {
+                domainRect->fBottom = textureContentArea->fBottom - kDomainInset;
+                needContentAreaConstraint = true;
+            }
+            if (!needContentAreaConstraint) {
+                return kNoDomain_DomainMode;
+            }
+        } else {
+            // Our sample coords for the texture are allowed to be outside the constraintRect so we
+            // don't consider it when computing the domain.
+            if (textureContentArea->fLeft != 0) {
+                domainRect->fLeft = textureContentArea->fLeft + kDomainInset;
+            }
+            if (textureContentArea->fTop != 0) {
+                domainRect->fTop = textureContentArea->fTop + kDomainInset;
+            }
+            if (textureContentArea->fRight != texW) {
+                domainRect->fRight = textureContentArea->fRight - kDomainInset;
+            }
+            if (textureContentArea->fBottom != texH) {
+                domainRect->fBottom = textureContentArea->fBottom - kDomainInset;
+            }
+        }
+    } else {
+        return kNoDomain_DomainMode;
+    }
+
+    if (domainRect->fLeft > domainRect->fRight) {
+        domainRect->fLeft = domainRect->fRight = SkScalarAve(domainRect->fLeft, domainRect->fRight);
+    }
+    if (domainRect->fTop > domainRect->fBottom) {
+        domainRect->fTop = domainRect->fBottom = SkScalarAve(domainRect->fTop, domainRect->fBottom);
+    }
+    domainRect->fLeft /= texW;
+    domainRect->fTop /= texH;
+    domainRect->fRight /= texW;
+    domainRect->fBottom /= texH;
+    return kDomain_DomainMode;
+}
+
+const GrFragmentProcessor* GrTextureAdjuster::createFragmentProcessor(
+                                        const SkMatrix& textureMatrix,
+                                        const SkRect& constraintRect,
+                                        FilterConstraint filterConstraint,
+                                        bool coordsLimitedToConstraintRect,
+                                        const GrTextureParams::FilterMode* filterOrNullForBicubic) {
+
+    const SkIRect* contentArea = this->contentAreaOrNull();
+
+    SkRect domain;
+    GrTexture* texture = this->originalTexture();
+    DomainMode domainMode =
+        determine_domain_mode(constraintRect, filterConstraint, coordsLimitedToConstraintRect,
+                              texture->width(), texture->height(),
+                              contentArea, filterOrNullForBicubic,
+                              &domain);
+    if (kTightCopy_DomainMode == domainMode) {
+        // TODO: Copy the texture and adjust the texture matrix (both parts need to consider
+        // non-int constraint rect)
+        // For now: treat as bilerp and ignore what goes on above level 0.
+
+        // We only expect MIP maps to require a tight copy.
+        SkASSERT(filterOrNullForBicubic &&
+                 GrTextureParams::kMipMap_FilterMode == *filterOrNullForBicubic);
+        static const GrTextureParams::FilterMode kBilerp = GrTextureParams::kBilerp_FilterMode;
+        domainMode =
+            determine_domain_mode(constraintRect, filterConstraint, coordsLimitedToConstraintRect,
+                                  texture->width(), texture->height(),
+                                  contentArea, &kBilerp, &domain);
+        SkASSERT(kTightCopy_DomainMode != domainMode);
+        filterOrNullForBicubic = &kBilerp;
+    }
+    SkASSERT(kNoDomain_DomainMode == domainMode ||
+             (domain.fLeft <= domain.fRight && domain.fTop <= domain.fBottom));
+    if (filterOrNullForBicubic) {
+        if (kDomain_DomainMode == domainMode) {
+            SkASSERT(*filterOrNullForBicubic != GrTextureParams::kMipMap_FilterMode);
+            return GrTextureDomainEffect::Create(texture, textureMatrix, domain,
+                                                 GrTextureDomain::kClamp_Mode,
+                                                 *filterOrNullForBicubic);
+        } else {
+            GrTextureParams params(SkShader::kClamp_TileMode, *filterOrNullForBicubic);
+            return GrSimpleTextureEffect::Create(texture, textureMatrix, params);
+        }
+    } else {
+        if (kDomain_DomainMode == domainMode) {
+            return GrBicubicEffect::Create(texture, textureMatrix, domain);
+        } else {
+            static const SkShader::TileMode kClampClamp[] =
+            { SkShader::kClamp_TileMode, SkShader::kClamp_TileMode };
+            return GrBicubicEffect::Create(texture, textureMatrix, kClampClamp);
+        }
+    }
+}
+
 //////////////////////////////////////////////////////////////////////////////
 
 GrTexture* GrTextureMaker::refTextureForParams(GrContext* ctx, const GrTextureParams& params) {