Adding my Bitmap2Path sample for 1on1 meeting.

BUG=
R=reed@google.com, borenet@google.com

Author: dierk@google.com

Review URL: https://chromiumcodereview.appspot.com/16829003

git-svn-id: http://skia.googlecode.com/svn/trunk@9843 2bbb7eff-a529-9590-31e7-b0007b416f81

bench/PathUtilsBench.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 "SkBenchmark.h"
+#include "SkCanvas.h"
+#include "SkPathUtils.h"
+#include "SkRandom.h"
+#include "SkTime.h"
+#include "SkString.h"
+
+#define H 16
+#define W 16
+#define STRIDE 2
+
+//this function is redefined for sample, test, and bench. is there anywhere
+// I can put it to avoid code duplcation?           
+static void fillRandomBits( int chars, char* bits ){
+    SkTime time;
+    SkMWCRandom rand = SkMWCRandom( time.GetMSecs() );
+
+    for (int i = 0; i < chars; ++i){
+        bits[i] = rand.nextU();
+    }
+}           
+
+static void path_proc(char* bits, SkPath* path) {
+    SkPathUtils::BitsToPath_Path(path, bits, H, W, STRIDE);
+}
+
+static void region_proc(char* bits, SkPath* path) {
+    SkPathUtils::BitsToPath_Region(path, bits, H, W, STRIDE);
+}
+
+/// Emulates the mix of rects blitted by gmail during scrolling
+class PathUtilsBench : public SkBenchmark {
+    typedef void (*Proc)(char*, SkPath*);
+
+    Proc fProc;
+    int fH, fW, fStride;
+    SkString fName;
+    char* bits[H * STRIDE];
+    
+    enum { N = SkBENCHLOOP(20) };
+
+public:
+    PathUtilsBench(void* param, Proc proc, const char name[]) : INHERITED(param) {
+        fProc = proc;
+        fName.printf("pathUtils_%s", name);
+        
+
+    }
+
+protected:
+    virtual const char* onGetName() { return fName.c_str(); }
+
+    virtual void onDraw(SkCanvas* canvas) {
+
+        for (int i = 0; i < N; ++i){
+            //create a random 16x16 bitmap
+            fillRandomBits(H * STRIDE, (char*) &bits);
+            
+            //use passed function pointer to handle it
+            SkPath path;
+            fProc( (char*) &bits, &path);
+        }
+    }
+
+private:
+    typedef SkBenchmark INHERITED;
+};
+
+static SkBenchmark* PU_path(void* p) { return SkNEW_ARGS(PathUtilsBench, (p, path_proc, "path")); } 
+static SkBenchmark* PU_region(void* p) { return SkNEW_ARGS(PathUtilsBench, (p, region_proc, "region")); } 
+
+static BenchRegistry PU_Path(PU_path);
+static BenchRegistry PU_Region(PU_region);

gyp/SampleApp.gyp

@@ -86,6 +86,7 @@
         '../samplecode/SamplePatch.cpp',
         '../samplecode/SamplePath.cpp',
         '../samplecode/SamplePathClip.cpp',
+        '../samplecode/SamplePathUtils.cpp',
         '../samplecode/SamplePathEffects.cpp',
         '../samplecode/SamplePicture.cpp',
         '../samplecode/SamplePictFile.cpp',

gyp/bench.gypi

@@ -44,6 +44,7 @@
     '../bench/MutexBench.cpp',
     '../bench/PathBench.cpp',
     '../bench/PathIterBench.cpp',
+    '../bench/PathUtilsBench.cpp',
     '../bench/PerlinNoiseBench.cpp',
     '../bench/PicturePlaybackBench.cpp',
     '../bench/PictureRecordBench.cpp',

gyp/tests.gyp

@@ -83,6 +83,7 @@
         '../tests/PathCoverageTest.cpp',
         '../tests/PathMeasureTest.cpp',
         '../tests/PathTest.cpp',
+        '../tests/PathUtilsTest.cpp',
         '../tests/PDFPrimitivesTest.cpp',
         '../tests/PictureTest.cpp',
         '../tests/PictureUtilsTest.cpp',

gyp/utils.gyp

@@ -12,6 +12,7 @@
         '../include/effects',
         '../include/images',
         '../include/lazy',
+        '../include/pathops',
         '../include/pipe',
         '../include/utils',
         '../include/utils/mac',
@@ -82,6 +83,7 @@
         '../src/utils/SkParseColor.cpp',
         '../src/utils/SkParsePath.cpp',
         '../src/utils/SkPictureUtils.cpp',
+        '../src/utils/SkPathUtils.cpp',
         '../src/utils/SkProxyCanvas.cpp',
         '../src/utils/SkSHA1.cpp',
         '../src/utils/SkSHA1.h',

include/utils/SkPathUtils.h

+/*
+ *  CAUTION: EXPERIMENTAL CODE
+ *
+ *  This code is not to be used and will not be supported
+ *  if it fails on you. DO NOT USE!
+ *
+ */
+
+#ifndef SkPathUtils_DEFINED
+#define SKPathUtils_DEFINED
+
+#include "SkPath.h"
+
+/*
+ * The following methods return the boundary path given a 1-bit bitmap, specified
+ * by width/height and stride. The bits are interpreted as 1 being "in" the path,
+ * and 0 being "out". The bits are interpreted as MSB on the left, and LSB on the right.
+ */
+
+class SK_API SkPathUtils {
+public:
+    /**
+       This variation iterates the binary data sequentially (as in scanline fashion)
+       and will add each run of 1's to the path as a rectangular path. Upon parsing
+       all binary data the path is simplified using the PathOps::Simplify() method.
+    */
+    static void BitsToPath_Path(SkPath* path, const char* bitmap,
+                            int h, int w, int stride);
+
+    /**
+       This variation utilizes the SkRegion class to generate paths, adding
+       each run of 1's to the SkRegion as an SkIRect. Upon parsing the entirety
+       of the binary the SkRegion is converted to a Path via getBoundaryPath().
+    */
+    static void BitsToPath_Region(SkPath* path, const char* bitmap,
+                                   int h, int w, int stride);
+
+};
+
+#endif

samplecode/SamplePathUtils.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SampleCode.h"
+#include "SkCanvas.h"
+#include "SkPathUtils.h"
+#include "SkView.h"
+//#include "SkPathOps.h" // loads fine here, won't in PathUtils src files
+#include "SkRandom.h"
+#include "SkTime.h"  
+
+class samplePathUtils : public SampleView {
+public:
+    samplePathUtils() {
+        bmp_paint.setAntiAlias(true);  // Black paint for bitmap
+	bmp_paint.setStyle(SkPaint::kFill_Style);
+        bmp_paint.setColor(SK_ColorBLACK);
+    }
+
+protected:
+    static const int numModes = 3;
+    static const int h=8, w=12, stride=2, scale=10; // stride is in bytes
+    static const int numChars = h * stride; // number of chars in entire array
+
+    SkPaint bmp_paint;
+    
+    // overrides from SkEventSink
+    virtual bool onQuery(SkEvent* evt) {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "PathUtils");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    /////////////////////////////////////////////////////////////
+    
+    virtual void onDrawContent(SkCanvas* canvas) {
+        // bitmap definitions
+        const char bits[numModes][numChars] = {
+            { 0x18, 0x00, 0x3c, 0x00, 0x7e, 0x00, 0xdb, 0x00,
+               0xff, 0x00, 0x24, 0x00, 0x5a, 0x00, 0xa5, 0x00 },
+            
+            { 0x20, 0x80, 0x91, 0x20, 0xbf, 0xa0, 0xee, 0xe0,
+              0xff, 0xe0, 0x7f, 0xc0, 0x20, 0x80, 0x40, 0x40 },
+
+            { 0x0f, 0x00, 0x7f, 0xe0, 0xff, 0xf0, 0xe6, 0x70,
+              0xff, 0xf0, 0x19, 0x80, 0x36, 0xc0, 0xc0, 0x30 }
+        };
+
+        for (int i = 0; i < numModes; ++i) {
+            SkPath path; // generate and simplify each path
+            SkPathUtils::BitsToPath_Path(&path, (char*) &bits[i], h, w, stride);
+            
+            canvas->save(); // DRAWING
+            canvas->scale(scale, scale);  // scales up each bitmap
+            canvas->translate(0, 1.5f * h * i);
+            canvas->drawPath(path, bmp_paint); // draw bitmap
+            canvas->restore();
+            
+            // use the SkRegion method
+            SkPath pathR;
+            SkPathUtils::BitsToPath_Region(&pathR, (char*) &bits[i], h, w, stride);
+            
+            canvas->save();
+            canvas->scale(scale, scale);  // scales up each bitmap
+            canvas->translate(1.5f * w, 1.5f * h * i); // translates past previous bitmap
+            canvas->drawPath(pathR, bmp_paint); // draw bitmap
+            canvas->restore();
+        }
+    }
+    
+private:
+    typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new samplePathUtils; }
+static SkViewRegister reg(MyFactory)
+;

src/utils/SkPathUtils.cpp

+/*
+ *  CAUTION: EXPERIMENTAL CODE
+ *
+ *  This code is not to be used and will not be supported
+ *  if it fails on you. DO NOT USE!
+ *
+ */
+
+#include "SkPathUtils.h"
+
+#include "SkPath.h"
+#include "SkPathOps.h" // this can't be found, how do I link it?
+#include "SkRegion.h"
+
+typedef void (*line2path)(SkPath*, const char*, int, int);
+#define SQRT_2 1.41421356237f
+#define ON  0xFF000000 // black pixel
+#define OFF 0x00000000 // transparent pixel
+
+// assumes stride is in bytes
+/*
+static void FillRandomBits( int chars, char* bits ){
+    SkTime time;
+    SkMWCRandom rand = SkMWCRandom( time.GetMSecs() );
+
+    for (int i = 0; i < chars; ++i){
+        bits[i] = rand.nextU();
+    }
+}OA
+*/    
+
+static int GetBit( const char* buffer, int x ) {
+    int byte = x >> 3;
+    int bit = x & 7;
+
+    return buffer[byte] & (128 >> bit);
+}
+
+/*
+static void Line2path_pixel(SkPath* path, const char* line,
+                            int lineIdx, int width) {
+    for (int i = 0; i < width; ++i) {
+        // simply makes every ON pixel into a rect path
+        if (GetBit(line,i)) {
+            path->addRect(SkRect::MakeXYWH(i, lineIdx, 1, 1),
+                          SkPath::kCW_Direction);
+        }
+    }
+}
+
+static void Line2path_pixelCircle(SkPath* path, const char* line,
+                                  int lineIdx, int width) {
+    for (int i = 0; i < width; ++i) {
+        // simply makes every ON pixel into a circle path
+        if (GetBit(line,i)) {
+            path->addCircle(i + SK_ScalarHalf,
+                            lineIdx + SK_ScalarHalf,
+                            SkFloatToScalar(SQRT_2 / 2.0f));
+        }
+    }
+}
+*/
+
+static void Line2path_span(SkPath* path, const char* line,
+                           int lineIdx, int width) {
+    bool inRun = 0;
+    int start = 1;
+
+    for (int i = 0; i < width; ++i) {
+        int curPixel = GetBit(line,i);
+
+        if ( (curPixel!=0) != inRun ) { // if transition
+            if (curPixel) { // if transition on
+                inRun = 1;
+                start = i; // mark beginning of span
+            }else { // if transition off add the span as a path
+                inRun = 0;
+                path->addRect(SkRect::MakeXYWH(start, lineIdx, i-start, 1),
+                              SkPath::kCW_Direction);
+            }
+        }
+    }
+
+    if (inRun==1) { // close any open spans
+        int end = 0;
+        if ( GetBit(line,width-1) ) ++end;
+        path->addRect(SkRect::MakeXYWH(start, lineIdx,
+                                       width - 1 + end - start, 1),
+                      SkPath::kCW_Direction);
+    } else if ( GetBit(line,width-1) ) { // if last pixel on add rect
+        path->addRect(SkRect::MakeXYWH(width-1, lineIdx, 1, 1),
+                      SkPath::kCW_Direction);
+    }
+}
+
+void SkPathUtils::BitsToPath_Path(SkPath* path,
+                        const char* bitmap,
+                        int h, int w, int stride) {
+    // loop for every line in bitmap
+    for (int i = 0; i < h; ++i) {
+        // fn ptr handles each line separately
+        //l2p_fn(path, &bitmap[i*stride], i, w);
+        Line2path_span(path, &bitmap[i*stride], i, w);
+    }
+    Simplify(*path, path); // simplify resulting bitmap
+}
+
+void SkPathUtils::BitsToPath_Region(SkPath* path,
+                               const char* bitmap,
+                               int h, int w, int stride) {
+    SkRegion region;
+
+    // loop for each line
+    for (int y = 0; y < h; ++y){
+        bool inRun = 0;
+        int start = 1;
+        const char* line = &bitmap[y * stride];
+        
+        // loop for each pixel 
+        for (int i = 0; i < w; ++i) {
+            int curPixel = GetBit(line,i);
+            
+            if ( (curPixel!=0) != inRun ) { // if transition
+                if (curPixel) { // if transition on
+                    inRun = 1;
+                    start = i; // mark beginning of span
+                }else { // if transition off add the span as a path
+                    inRun = 0;
+                    //add here
+                    region.op(SkIRect::MakeXYWH(start, y, i-start, 1),
+                              SkRegion::kUnion_Op );
+                }
+            }
+        }
+        if (inRun==1) { // close any open spans
+            int end = 0;
+            if ( GetBit(line,w-1) ) ++end;
+            // add the thing here
+            region.op(SkIRect::MakeXYWH(start, y, w-1-start+end, 1),
+                      SkRegion::kUnion_Op );
+            
+        } else if ( GetBit(line,w-1) ) { // if last pixel on add rect
+            // add the thing here
+            region.op(SkIRect::MakeXYWH(w-1, y, 1, 1),
+                      SkRegion::kUnion_Op );
+        }
+    }
+    // convert region to path
+    region.getBoundaryPath(path);
+}

tests/PathUtilsTest.cpp

+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+
+#include "SkBitmap.h"
+#include "SkCanvas.h"
+#include "SkPathUtils.h"
+#include "SkRandom.h"
+#include "SkTime.h"
+
+#define NUM_IT 100000
+#define ON  0xFF000000 // black pixel
+#define OFF 0x00000000 // transparent pixel    
+
+class SkBitmap;
+
+//this function is redefined for sample, test, and bench. is there anywhere
+// I can put it to avoid code duplcation?           
+static void fillRandomBits( int chars, char* bits ){
+    SkTime time;
+    SkMWCRandom rand = SkMWCRandom( time.GetMSecs() );
+
+    for (int i = 0; i < chars; ++i){
+        bits[i] = rand.nextU();
+    }
+}
+
+//also defined within PathUtils.cpp, but not in scope here. Anyway to call it
+// without re-defining it?
+static int getBit( const char* buffer, int x ) {
+    int byte = x >> 3;
+    int bit = x & 7;
+
+    return buffer[byte] & (1 << bit);
+}
+
+static void bin2SkBitmap(const char* bin_bmp, SkBitmap* sk_bmp,
+                               int h, int w, int stride){
+    //init the SkBitmap
+    sk_bmp->setConfig(SkBitmap::kARGB_8888_Config, w, h);
+    sk_bmp->allocPixels();
+
+    for (int y = 0; y < h; ++y) { // for every row
+
+        const char* curLine = &bin_bmp[y * stride];
+        for (int x = 0; x < w; ++x) {// for every pixel
+            if (getBit(curLine, x)) {
+                *sk_bmp->getAddr32(x,y) = ON;
+            }
+            else {
+                *sk_bmp->getAddr32(x,y) = OFF;
+            }
+        }
+    }
+}
+
+static bool test_bmp(skiatest::Reporter* reporter,
+                      const SkBitmap* bmp1, const SkBitmap* bmp2,
+                      int h, int w) {
+    for (int y = 0; y < h; ++y) { // loop through all pixels
+        for (int x = 0; x < w; ++x) {
+            REPORTER_ASSERT( reporter, *bmp1->getAddr32(x,y) == *bmp1->getAddr32(x,y) );
+        }
+    }
+    return true;
+}
+
+static void test_path_eq(skiatest::Reporter* reporter, const SkPath* path,
+                      const SkBitmap* truth, int h, int w){
+    // make paint
+    SkPaint bmpPaint;
+    bmpPaint.setAntiAlias(true);  // Black paint for bitmap
+    bmpPaint.setStyle(SkPaint::kFill_Style);
+    bmpPaint.setColor(SK_ColorBLACK);
+    
+    // make bmp
+    SkBitmap bmp;
+    bmp.setConfig(SkBitmap::kARGB_8888_Config, w, h);
+    bmp.allocPixels();
+    SkCanvas(bmp).drawPath(*path, bmpPaint);
+
+    // test bmp
+    test_bmp(reporter, &bmp, truth, h, w);
+}
+
+static void test_path(skiatest::Reporter* reporter, const SkBitmap* truth,
+                            const char* bin_bmp, int h, int w, int stride){
+    // make path
+    SkPath path;
+    SkPathUtils::BitsToPath_Path(&path, bin_bmp, h, w, stride);
+    
+    //test for correctness
+    test_path_eq(reporter, &path, truth, h, w);
+}
+
+static void test_region(skiatest::Reporter* reporter, const SkBitmap* truth,
+                            const char* bin_bmp, int h, int w, int stride){
+    //generate bitmap
+    SkPath path;
+    SkPathUtils::BitsToPath_Region(&path, bin_bmp, h, w, stride);
+    
+    //test for correctness
+    test_path_eq(reporter, &path, truth, h, w);
+}
+
+static void TestPathUtils(skiatest::Reporter* reporter) {
+    const int w[4] = {4, 8, 12, 16};
+    int h = 8, stride = 4;
+    char bits[ h * stride ];
+    static char* bin_bmp = &bits[0];
+
+    //loop to run randomized test lots of times
+    for (int it = 0; it < NUM_IT; ++it)
+    {
+        // generate a random binary bitmap
+        fillRandomBits( h * stride, bin_bmp); // generate random bitmap    
+    
+        // for each bitmap width, use subset of binary bitmap
+        for (int i = 0; i < 4; ++i) {
+            // generate truth bitmap
+            SkBitmap bmpTruth;
+            bin2SkBitmap(bin_bmp, &bmpTruth, h, w[i], stride);
+
+            test_path(reporter, &bmpTruth, bin_bmp, h, w[i], stride);
+            test_region(reporter, &bmpTruth, bin_bmp, h, w[i], stride);
+        }
+    }
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("PathUtils", PathUtils, TestPathUtils)