rename gamma to table, since it is more general than just gamma

git-svn-id: http://skia.googlecode.com/svn/trunk@412 2bbb7eff-a529-9590-31e7-b0007b416f81

include/effects/SkTableMaskFilter.h

@@ -14,27 +14,45 @@
  * limitations under the License.
  */
 
-#ifndef SkGammaMaskFilter_DEFINED
-#define SkGammaMaskFilter_DEFINED
+#ifndef SkTableMaskFilter_DEFINED
+#define SkTableMaskFilter_DEFINED
 
 #include "SkMaskFilter.h"
 #include "SkScalar.h"
 
-/** \class SkGammaMaskFilter
+/** \class SkTableMaskFilter
  
     Applies a table lookup on each of the alpha values in the mask.
-    An arbitrary table can be assigned, or a gamma (pow) table is computed
-    based on the specified exponent.
+    Helper methods create some common tables (e.g. gamma, clipping)
  */
-class SkGammaMaskFilter : public SkMaskFilter {
+class SkTableMaskFilter : public SkMaskFilter {
 public:
-    SkGammaMaskFilter();
-    SkGammaMaskFilter(SkScalar gamma);
-    SkGammaMaskFilter(const uint8_t table[256]);
-    virtual ~SkGammaMaskFilter();
+    SkTableMaskFilter();
+    SkTableMaskFilter(const uint8_t table[256]);
+    virtual ~SkTableMaskFilter();
 
-    void setGamma(SkScalar gamma);
-    void setGammaTable(const uint8_t table[256]);
+    void setTable(const uint8_t table[256]);
+
+    /** Utility that sets the gamma table
+     */
+    static void MakeGammaTable(uint8_t table[256], SkScalar gamma);
+
+    /** Utility that creates a clipping table: clamps values below min to 0
+        and above max to 255, and rescales the remaining into 0..255
+     */
+    static void MakeClipTable(uint8_t table[256], uint8_t min, uint8_t max);
+
+    static SkTableMaskFilter* CreateGamma(SkScalar gamma) {
+        uint8_t table[256];
+        MakeGammaTable(table, gamma);
+        return SkNEW_ARGS(SkTableMaskFilter, (table));
+    }
+
+    static SkTableMaskFilter* CreateClip(uint8_t min, uint8_t max) {
+        uint8_t table[256];
+        MakeClipTable(table, min, max);
+        return SkNEW_ARGS(SkTableMaskFilter, (table));
+    }
 
     // overrides from SkMaskFilter
     virtual SkMask::Format getFormat();
@@ -45,7 +63,7 @@ public:
     virtual Factory getFactory();
 
 protected:
-    SkGammaMaskFilter(SkFlattenableReadBuffer& rb);
+    SkTableMaskFilter(SkFlattenableReadBuffer& rb);
     static SkFlattenable* Factory(SkFlattenableReadBuffer&);
 
 private:

samplecode/SampleWarp.cpp

@@ -8,6 +8,84 @@
 #include "SkUtils.h"
 #include "SkImageDecoder.h"
 
+#include "SkBlurMaskFilter.h"
+#include "SkTableMaskFilter.h"
+
+static void test_bigblur(SkCanvas* canvas) {
+    canvas->drawColor(SK_ColorBLACK);
+
+    SkBitmap orig, mask;
+    SkImageDecoder::DecodeFile("/skimages/app_icon.png", &orig);
+
+    SkMaskFilter* mf = SkBlurMaskFilter::Create(8, SkBlurMaskFilter::kNormal_BlurStyle);
+    SkPaint paint;
+    paint.setMaskFilter(mf)->unref();
+    SkIPoint offset;
+    orig.extractAlpha(&mask, &paint, &offset);
+
+    paint.setColor(0xFFBB8800);
+    paint.setColor(SK_ColorWHITE);
+
+    int i;
+    canvas->save();
+    float gamma = 0.8;
+    for (i = 0; i < 5; i++) {
+        paint.setMaskFilter(SkTableMaskFilter::CreateGamma(gamma))->unref();
+        canvas->drawBitmap(mask, 0, 0, &paint);
+        paint.setMaskFilter(NULL);
+        canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+        gamma -= 0.1;
+        canvas->translate(120, 0);
+    }
+    canvas->restore();
+    canvas->translate(0, 160);
+
+    for (i = 0; i < 5; i++) {
+        paint.setMaskFilter(SkTableMaskFilter::CreateClip(i*30, 255 - 20))->unref();
+        canvas->drawBitmap(mask, 0, 0, &paint);
+        paint.setMaskFilter(NULL);
+        canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+        canvas->translate(120, 0);
+    }
+
+#if 0
+    paint.setColor(0xFFFFFFFF);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    paint.setMaskFilter(NULL);
+    canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+    
+    canvas->translate(120, 0);
+    
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+    
+    canvas->translate(120, 0);
+    
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+    
+    canvas->translate(120, 0);
+    
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+    
+    canvas->translate(120, 0);
+    
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(mask, 0, 0, &paint);
+    canvas->drawBitmap(orig, -offset.fX, -offset.fY, &paint);
+#endif
+}
+
 #include "SkMeshUtils.h"
 
 static SkPoint SkMakePoint(SkScalar x, SkScalar y) {
@@ -240,9 +318,6 @@ void Mesh::drawWireframe(SkCanvas* canvas, const SkPaint& paint) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkScalar gScale = 0;
-static SkScalar gDScale = 0.02;
-
 class WarpView : public SkView {
     Mesh        fMesh, fOrig;
     SkBitmap    fBitmap;
@@ -282,7 +357,8 @@ protected:
     }
     
     virtual void onDraw(SkCanvas* canvas) {
-        canvas->drawColor(SK_ColorGRAY);
+        canvas->drawColor(SK_ColorLTGRAY);
+     //   test_bigblur(canvas); return;
         
         SkPaint paint;
         paint.setFilterBitmap(true);
@@ -295,18 +371,7 @@ protected:
         paint.setColor(SK_ColorRED);
     //    fMesh.draw(canvas, paint);
 
-#if 0
-        test_patch(canvas, fBitmap, gScale);
-        gScale += gDScale;
-        if (gScale > 2) {
-            gDScale = -gDScale;
-        } else if (gScale < -2) {
-            gDScale = -gDScale;
-        }
-        this->inval(NULL);
-#else
         test_drag(canvas, fBitmap, fP0, fP1);
-#endif
     }
     
     virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {

src/effects/SkGammaMaskFilter.cpp

@@ -1,95 +0,0 @@
-#include "SkGammaMaskFilter.h"
-
-SkGammaMaskFilter::SkGammaMaskFilter() {
-    for (int i = 0; i < 256; i++) {
-        fTable[i] = i;
-    }
-}
-
-SkGammaMaskFilter::SkGammaMaskFilter(SkScalar gamma) {
-    this->setGamma(gamma);
-}
-
-SkGammaMaskFilter::SkGammaMaskFilter(const uint8_t table[256]) {
-    this->setGammaTable(table);
-}
-
-SkGammaMaskFilter::~SkGammaMaskFilter() {}
-
-void SkGammaMaskFilter::setGamma(SkScalar gamma) {
-    float x = 0;
-    const float dx = 1 / 255.0f;
-    for (int i = 0; i < 256; i++) {
-        fTable[i] = SkPin32(SkScalarRound(powf(x, gamma) * 255), 0, 255);
-        x += dx;
-    }
-}
-
-void SkGammaMaskFilter::setGammaTable(const uint8_t table[256]) {
-    memcpy(fTable, table, 256);
-}
-
-SkMask::Format SkGammaMaskFilter::getFormat() {
-    return SkMask::kA8_Format;
-}
-
-bool SkGammaMaskFilter::filterMask(SkMask* dst, const SkMask& src,
-                                 const SkMatrix&, SkIPoint* margin) {
-    if (src.fFormat != SkMask::kA8_Format) {
-        return false;
-    }
-
-    dst->fBounds = src.fBounds;
-    dst->fRowBytes = SkAlign4(dst->fBounds.width());
-    dst->fFormat = SkMask::kA8_Format;
-    dst->fImage = NULL;
-    
-    if (src.fImage) {
-        dst->fImage = SkMask::AllocImage(dst->computeImageSize());
-        
-        const uint8_t* srcP = src.fImage;
-        uint8_t* dstP = dst->fImage;
-        const uint8_t* table = fTable;
-        int dstWidth = dst->fBounds.width();
-        int extraZeros = dst->fRowBytes - dstWidth;
-        
-        for (int y = dst->fBounds.height() - 1; y >= 0; --y) {
-            for (int x = dstWidth - 1; x >= 0; --x) {
-                dstP[x] = table[srcP[x]];
-            }
-            srcP += src.fRowBytes;
-            // we can't just inc dstP by rowbytes, because if it has any
-            // padding between its width and its rowbytes, we need to zero those
-            // so that the bitters can read those safely if that is faster for
-            // them
-            dstP += dstWidth;
-            for (int i = extraZeros - 1; i >= 0; --i) {
-                *dstP++ = 0;
-            }
-        }
-    }
-
-    if (margin) {
-        margin->set(0, 0);
-    }
-    return true;
-}
-
-void SkGammaMaskFilter::flatten(SkFlattenableWriteBuffer& wb) {
-    this->INHERITED::flatten(wb);
-    wb.writePad(fTable, 256);
-}
-
-SkGammaMaskFilter::SkGammaMaskFilter(SkFlattenableReadBuffer& rb)
-        : INHERITED(rb) {
-    rb.read(fTable, 256);
-}
-
-SkFlattenable* SkGammaMaskFilter::Factory(SkFlattenableReadBuffer& rb) {
-    return SkNEW_ARGS(SkGammaMaskFilter, (rb));
-}
-
-SkFlattenable::Factory SkGammaMaskFilter::getFactory() {
-    return SkGammaMaskFilter::Factory;
-}
-

src/effects/SkTableMaskFilter.cpp

@@ -0,0 +1,127 @@
+#include "SkTableMaskFilter.h"
+
+SkTableMaskFilter::SkTableMaskFilter() {
+    for (int i = 0; i < 256; i++) {
+        fTable[i] = i;
+    }
+}
+
+SkTableMaskFilter::SkTableMaskFilter(const uint8_t table[256]) {
+    this->setTable(table);
+}
+
+SkTableMaskFilter::~SkTableMaskFilter() {}
+
+void SkTableMaskFilter::setTable(const uint8_t table[256]) {
+    memcpy(fTable, table, 256);
+}
+
+bool SkTableMaskFilter::filterMask(SkMask* dst, const SkMask& src,
+                                 const SkMatrix&, SkIPoint* margin) {
+    if (src.fFormat != SkMask::kA8_Format) {
+        return false;
+    }
+
+    dst->fBounds = src.fBounds;
+    dst->fRowBytes = SkAlign4(dst->fBounds.width());
+    dst->fFormat = SkMask::kA8_Format;
+    dst->fImage = NULL;
+    
+    if (src.fImage) {
+        dst->fImage = SkMask::AllocImage(dst->computeImageSize());
+        
+        const uint8_t* srcP = src.fImage;
+        uint8_t* dstP = dst->fImage;
+        const uint8_t* table = fTable;
+        int dstWidth = dst->fBounds.width();
+        int extraZeros = dst->fRowBytes - dstWidth;
+        
+        for (int y = dst->fBounds.height() - 1; y >= 0; --y) {
+            for (int x = dstWidth - 1; x >= 0; --x) {
+                dstP[x] = table[srcP[x]];
+            }
+            srcP += src.fRowBytes;
+            // we can't just inc dstP by rowbytes, because if it has any
+            // padding between its width and its rowbytes, we need to zero those
+            // so that the bitters can read those safely if that is faster for
+            // them
+            dstP += dstWidth;
+            for (int i = extraZeros - 1; i >= 0; --i) {
+                *dstP++ = 0;
+            }
+        }
+    }
+
+    if (margin) {
+        margin->set(0, 0);
+    }
+    return true;
+}
+
+SkMask::Format SkTableMaskFilter::getFormat() {
+    return SkMask::kA8_Format;
+}
+
+void SkTableMaskFilter::flatten(SkFlattenableWriteBuffer& wb) {
+    this->INHERITED::flatten(wb);
+    wb.writePad(fTable, 256);
+}
+
+SkTableMaskFilter::SkTableMaskFilter(SkFlattenableReadBuffer& rb)
+        : INHERITED(rb) {
+    rb.read(fTable, 256);
+}
+
+SkFlattenable* SkTableMaskFilter::Factory(SkFlattenableReadBuffer& rb) {
+    return SkNEW_ARGS(SkTableMaskFilter, (rb));
+}
+
+SkFlattenable::Factory SkTableMaskFilter::getFactory() {
+    return SkTableMaskFilter::Factory;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+void SkTableMaskFilter::MakeGammaTable(uint8_t table[256], SkScalar gamma) {
+    float x = 0;
+    const float dx = 1 / 255.0f;
+    for (int i = 0; i < 256; i++) {
+        table[i] = SkPin32(SkScalarRound(powf(x, gamma) * 255), 0, 255);
+        x += dx;
+    }
+}
+
+void SkTableMaskFilter::MakeClipTable(uint8_t table[256], uint8_t min,
+                                      uint8_t max) {
+    if (0 == max) {
+        max = 1;
+    }
+    if (min >= max) {
+        min = max - 1;
+    }
+    SkASSERT(min < max);
+
+    SkFixed scale = (1 << 16) * 255 / (max - min);
+    memset(table, 0, min + 1);
+    for (int i = min + 1; i < max; i++) {
+        int value = SkFixedRound(scale * (i - min));
+        SkASSERT(value <= 255);
+        table[i] = value;
+    }
+    memset(table + max, 255, 256 - max);
+
+#if 0
+    int j;
+    for (j = 0; j < 256; j++) {
+        if (table[j]) {
+            break;
+        }
+    }
+    SkDebugf("%d %d start [%d]", min, max, j);
+    for (; j < 256; j++) {
+        SkDebugf(" %d", table[j]);
+    }
+    SkDebugf("\n\n");
+#endif
+}
+