HQ filtering for tiled/bleed drawBitmap
sample at pix center in bicubic
R=senorblanco@chromium.org, jvanverth@google.com
Author: bsalomon@google.com
Review URL: https://codereview.chromium.org/83153006
git-svn-id: http://skia.googlecode.com/svn/trunk/src@12440 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/SkGpuDevice.cpp b/gpu/SkGpuDevice.cpp
index 6fb1403..07a946e 100644
--- a/gpu/SkGpuDevice.cpp
+++ b/gpu/SkGpuDevice.cpp
@@ -7,6 +7,7 @@
#include "SkGpuDevice.h"
+#include "effects/GrBicubicEffect.h"
#include "effects/GrTextureDomainEffect.h"
#include "effects/GrSimpleTextureEffect.h"
@@ -1057,22 +1058,29 @@
SkCanvas::kNone_DrawBitmapRectFlag);
}
-// This method outsets 'iRect' by 1 all around and then clamps its extents to
+// This method outsets 'iRect' by 'outset' all around and then clamps its extents to
// 'clamp'. 'offset' is adjusted to remain positioned over the top-left corner
// of 'iRect' for all possible outsets/clamps.
-static inline void clamped_unit_outset_with_offset(SkIRect* iRect, SkPoint* offset,
- const SkIRect& clamp) {
- iRect->outset(1, 1);
+static inline void clamped_outset_with_offset(SkIRect* iRect,
+ int outset,
+ SkPoint* offset,
+ const SkIRect& clamp) {
+ iRect->outset(outset, outset);
- if (iRect->fLeft < clamp.fLeft) {
+ int leftClampDelta = clamp.fLeft - iRect->fLeft;
+ if (leftClampDelta > 0) {
+ offset->fX -= outset - leftClampDelta;
iRect->fLeft = clamp.fLeft;
} else {
- offset->fX -= SK_Scalar1;
+ offset->fX -= outset;
}
- if (iRect->fTop < clamp.fTop) {
+
+ int topClampDelta = clamp.fTop - iRect->fTop;
+ if (topClampDelta > 0) {
+ offset->fY -= outset - topClampDelta;
iRect->fTop = clamp.fTop;
} else {
- offset->fY -= SK_Scalar1;
+ offset->fY -= outset;
}
if (iRect->fRight > clamp.fRight) {
@@ -1092,10 +1100,17 @@
CHECK_SHOULD_DRAW(draw, false);
SkRect srcRect;
+ // If there is no src rect, or the src rect contains the entire bitmap then we're effectively
+ // in the (easier) bleed case, so update flags.
if (NULL == srcRectPtr) {
srcRect.set(0, 0, SkIntToScalar(bitmap.width()), SkIntToScalar(bitmap.height()));
+ flags = (SkCanvas::DrawBitmapRectFlags) (flags | SkCanvas::kBleed_DrawBitmapRectFlag);
} else {
srcRect = *srcRectPtr;
+ if (srcRect.fLeft <= 0 && srcRect.fTop <= 0 &&
+ srcRect.fRight >= bitmap.width() && srcRect.fBottom >= bitmap.height()) {
+ flags = (SkCanvas::DrawBitmapRectFlags) (flags | SkCanvas::kBleed_DrawBitmapRectFlag);
+ }
}
if (paint.getMaskFilter()){
@@ -1148,47 +1163,59 @@
GrTextureParams params;
SkPaint::FilterLevel paintFilterLevel = paint.getFilterLevel();
GrTextureParams::FilterMode textureFilterMode;
+
+ int tileFilterPad;
+ bool doBicubic = false;
+
switch(paintFilterLevel) {
case SkPaint::kNone_FilterLevel:
+ tileFilterPad = 0;
textureFilterMode = GrTextureParams::kNone_FilterMode;
break;
case SkPaint::kLow_FilterLevel:
+ tileFilterPad = 1;
textureFilterMode = GrTextureParams::kBilerp_FilterMode;
break;
case SkPaint::kMedium_FilterLevel:
+ tileFilterPad = 1;
textureFilterMode = GrTextureParams::kMipMap_FilterMode;
break;
case SkPaint::kHigh_FilterLevel:
- // Fall back to mips for now
- textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+ if (flags & SkCanvas::kBleed_DrawBitmapRectFlag) {
+ // We will install an effect that does the filtering in the shader.
+ textureFilterMode = GrTextureParams::kNone_FilterMode;
+ tileFilterPad = GrBicubicEffect::kFilterTexelPad;
+ doBicubic = true;
+ } else {
+ // We don't yet support doing bicubic filtering with an interior clamp. Fall back
+ // to MIPs
+ textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+ tileFilterPad = 1;
+ }
break;
default:
SkErrorInternals::SetError( kInvalidPaint_SkError,
"Sorry, I don't understand the filtering "
"mode you asked for. Falling back to "
"MIPMaps.");
+ tileFilterPad = 1;
textureFilterMode = GrTextureParams::kMipMap_FilterMode;
break;
-
}
params.setFilterMode(textureFilterMode);
- int maxTileSize = fContext->getMaxTextureSize();
- if (SkPaint::kNone_FilterLevel != paint.getFilterLevel()) {
- // We may need a skosh more room if we have to bump out the tile
- // by 1 pixel all around
- maxTileSize -= 2;
- }
+ int maxTileSize = fContext->getMaxTextureSize() - 2 * tileFilterPad;
int tileSize;
SkIRect clippedSrcRect;
if (this->shouldTileBitmap(bitmap, params, srcRectPtr, maxTileSize, &tileSize,
&clippedSrcRect)) {
- this->drawTiledBitmap(bitmap, srcRect, clippedSrcRect, params, paint, flags, tileSize);
+ this->drawTiledBitmap(bitmap, srcRect, clippedSrcRect, params, paint, flags, tileSize,
+ doBicubic);
} else {
// take the simple case
- this->internalDrawBitmap(bitmap, srcRect, params, paint, flags);
+ this->internalDrawBitmap(bitmap, srcRect, params, paint, flags, doBicubic);
}
}
@@ -1200,7 +1227,8 @@
const GrTextureParams& params,
const SkPaint& paint,
SkCanvas::DrawBitmapRectFlags flags,
- int tileSize) {
+ int tileSize,
+ bool bicubic) {
SkRect clippedSrcRect = SkRect::Make(clippedSrcIRect);
int nx = bitmap.width() / tileSize;
@@ -1227,7 +1255,7 @@
SkPoint offset = SkPoint::Make(SkIntToScalar(iTileR.fLeft),
SkIntToScalar(iTileR.fTop));
- if (SkPaint::kNone_FilterLevel != paint.getFilterLevel()) {
+ if (SkPaint::kNone_FilterLevel != paint.getFilterLevel() || bicubic) {
SkIRect iClampRect;
if (SkCanvas::kBleed_DrawBitmapRectFlag & flags) {
@@ -1235,13 +1263,15 @@
// but stay within the bitmap bounds
iClampRect = SkIRect::MakeWH(bitmap.width(), bitmap.height());
} else {
+ SkASSERT(!bicubic); // Bicubic is not supported with non-bleed yet.
+
// In texture-domain/clamp mode we only want to expand the
// tile on edges interior to "srcRect" (i.e., we want to
// not bleed across the original clamped edges)
srcRect.roundOut(&iClampRect);
}
-
- clamped_unit_outset_with_offset(&iTileR, &offset, iClampRect);
+ int outset = bicubic ? GrBicubicEffect::kFilterTexelPad : 1;
+ clamped_outset_with_offset(&iTileR, outset, &offset, iClampRect);
}
if (bitmap.extractSubset(&tmpB, iTileR)) {
@@ -1251,7 +1281,7 @@
tmpM.setTranslate(offset.fX, offset.fY);
GrContext::AutoMatrix am;
am.setPreConcat(fContext, tmpM);
- this->internalDrawBitmap(tmpB, tileR, params, paint, flags);
+ this->internalDrawBitmap(tmpB, tileR, params, paint, flags, bicubic);
}
}
}
@@ -1310,7 +1340,8 @@
const SkRect& srcRect,
const GrTextureParams& params,
const SkPaint& paint,
- SkCanvas::DrawBitmapRectFlags flags) {
+ SkCanvas::DrawBitmapRectFlags flags,
+ bool bicubic) {
SkASSERT(bitmap.width() <= fContext->getMaxTextureSize() &&
bitmap.height() <= fContext->getMaxTextureSize());
@@ -1332,6 +1363,7 @@
bool needsTextureDomain = false;
if (!(flags & SkCanvas::kBleed_DrawBitmapRectFlag) &&
params.filterMode() != GrTextureParams::kNone_FilterMode) {
+ SkASSERT(!bicubic);
// Need texture domain if drawing a sub rect.
needsTextureDomain = srcRect.width() < bitmap.width() ||
srcRect.height() < bitmap.height();
@@ -1376,6 +1408,8 @@
textureDomain,
GrTextureDomainEffect::kClamp_WrapMode,
params.filterMode()));
+ } else if (bicubic) {
+ effect.reset(GrBicubicEffect::Create(texture, SkMatrix::I(), params));
} else {
effect.reset(GrSimpleTextureEffect::Create(texture, SkMatrix::I(), params));
}
diff --git a/gpu/effects/GrBicubicEffect.cpp b/gpu/effects/GrBicubicEffect.cpp
index f6cc37d..cd013cb 100644
--- a/gpu/effects/GrBicubicEffect.cpp
+++ b/gpu/effects/GrBicubicEffect.cpp
@@ -73,8 +73,14 @@
"\tvec4 c = coefficients * ts;\n"
"\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
&cubicBlendName);
- builder->fsCodeAppendf("\tvec2 coord = %s - %s * vec2(0.5, 0.5);\n", coords2D.c_str(), imgInc);
- builder->fsCodeAppendf("\tvec2 f = fract(coord / %s);\n", imgInc);
+ builder->fsCodeAppendf("\tvec2 coord = %s - %s * vec2(0.5);\n", coords2D.c_str(), imgInc);
+ // We unnormalize the coord in order to determine our fractional offset (f) within the texel
+ // We then snap coord to a texel center and renormalize. The snap prevents cases where the
+ // starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
+ // double hit a texel.
+ builder->fsCodeAppendf("\tcoord /= %s;\n", imgInc);
+ builder->fsCodeAppend("\tvec2 f = fract(coord);\n");
+ builder->fsCodeAppendf("\tcoord = (coord - f + vec2(0.5)) * %s;\n", imgInc);
for (int y = 0; y < 4; ++y) {
for (int x = 0; x < 4; ++x) {
SkString coord;
diff --git a/gpu/effects/GrBicubicEffect.h b/gpu/effects/GrBicubicEffect.h
index eabc79f..d8c431a 100644
--- a/gpu/effects/GrBicubicEffect.h
+++ b/gpu/effects/GrBicubicEffect.h
@@ -17,6 +17,10 @@
class GrBicubicEffect : public GrSingleTextureEffect {
public:
+ enum {
+ kFilterTexelPad = 2, // Given a src rect in texels to be filtered, this number of
+ // surrounding texels are needed by the kernel in x and y.
+ };
virtual ~GrBicubicEffect();
static const char* Name() { return "Bicubic"; }
