Moved SW path renderer from GrContext.cpp to GrSoftwarePathRenderer.cpp

http://codereview.appspot.com/6138056/



git-svn-id: http://skia.googlecode.com/svn/trunk@3807 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrSoftwarePathRenderer.cpp b/src/gpu/GrSoftwarePathRenderer.cpp
index c591ac5..6780e0f 100644
--- a/src/gpu/GrSoftwarePathRenderer.cpp
+++ b/src/gpu/GrSoftwarePathRenderer.cpp
@@ -7,21 +7,203 @@
  */
 
 #include "GrSoftwarePathRenderer.h"
+#include "GrPaint.h"
+#include "SkPaint.h"
+#include "GrRenderTarget.h" 
+#include "GrContext.h"
+#include "SkDraw.h"
+#include "SkRasterClip.h"
 
-
+////////////////////////////////////////////////////////////////////////////////
 bool GrSoftwarePathRenderer::canDrawPath(const SkPath& path,
                                          GrPathFill fill,
                                          const GrDrawTarget* target,
                                          bool antiAlias) const {
-    if (!antiAlias) {
-        // TODO: the SW renderer can also handle non-AA paths
+    if (!antiAlias || NULL == fContext) {
+        // TODO: We could allow the SW path to also handle non-AA paths but
+        // this would mean that GrDefaultPathRenderer would never be called
+        // (since it appears after the SW renderer in the path renderer
+        // chain). Some testing would need to be done r.e. performance 
+        // and consistency of the resulting images before removing
+        // the "!antiAlias" clause from the above test
         return false;
     }
 
-    // TODO: set to true when filled out
-    return false;
+    return true;
 }
 
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+SkPath::FillType gr_fill_to_sk_fill(GrPathFill fill) {
+    switch (fill) {
+        case kWinding_PathFill:
+            return SkPath::kWinding_FillType;
+        case kEvenOdd_PathFill:
+            return SkPath::kEvenOdd_FillType;
+        case kInverseWinding_PathFill:
+            return SkPath::kInverseWinding_FillType;
+        case kInverseEvenOdd_PathFill:
+            return SkPath::kInverseEvenOdd_FillType;
+        default:
+            GrCrash("Unexpected fill.");
+            return SkPath::kWinding_FillType;
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// gets device coord bounds of path (not considering the fill) and clip. The
+// path bounds will be a subset of the clip bounds. returns false if 
+// path bounds would be empty.
+bool get_path_and_clip_bounds(const GrDrawTarget* target,
+                              const SkPath& path,
+                              const GrVec* translate,
+                              GrIRect* pathBounds,
+                              GrIRect* clipBounds) {
+    // compute bounds as intersection of rt size, clip, and path
+    const GrRenderTarget* rt = target->getDrawState().getRenderTarget();
+    if (NULL == rt) {
+        return false;
+    }
+    *pathBounds = GrIRect::MakeWH(rt->width(), rt->height());
+    const GrClip& clip = target->getClip();
+    if (clip.hasConservativeBounds()) {
+        clip.getConservativeBounds().roundOut(clipBounds);
+        if (!pathBounds->intersect(*clipBounds)) {
+            return false;
+        }
+    } else {
+        // pathBounds is currently the rt extent, set clip bounds to that rect.
+        *clipBounds = *pathBounds;
+    }
+    GrRect pathSBounds = path.getBounds();
+    if (!pathSBounds.isEmpty()) {
+        if (NULL != translate) {
+            pathSBounds.offset(*translate);
+        }
+        target->getDrawState().getViewMatrix().mapRect(&pathSBounds,
+                                                        pathSBounds);
+        GrIRect pathIBounds;
+        pathSBounds.roundOut(&pathIBounds);
+        if (!pathBounds->intersect(pathIBounds)) {
+            return false;
+        }
+    } else {
+        return false;
+    }
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/**
+ * sw rasterizes path to A8 mask using the context's matrix and uploads to a 
+ * scratch texture.
+ */
+
+bool sw_draw_path_to_mask_texture(const SkPath& clientPath,
+                                  const GrIRect& pathDevBounds,
+                                  GrPathFill fill,
+                                  GrContext* context,
+                                  const GrPoint* translate,
+                                  GrAutoScratchTexture* tex,
+                                  bool antiAlias) {
+    SkPaint paint;
+    SkPath tmpPath;
+    const SkPath* pathToDraw = &clientPath;
+    if (kHairLine_PathFill == fill) {
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setStrokeWidth(SK_Scalar1);
+    } else {
+        paint.setStyle(SkPaint::kFill_Style);
+        SkPath::FillType skfill = gr_fill_to_sk_fill(fill);
+        if (skfill != pathToDraw->getFillType()) {
+            tmpPath = *pathToDraw;
+            tmpPath.setFillType(skfill);
+            pathToDraw = &tmpPath;
+        }
+    }
+    paint.setAntiAlias(antiAlias);
+    paint.setColor(SK_ColorWHITE);
+
+    GrMatrix matrix = context->getMatrix();
+    if (NULL != translate) {
+        matrix.postTranslate(translate->fX, translate->fY);
+    }
+
+    matrix.postTranslate(-pathDevBounds.fLeft * SK_Scalar1,
+                         -pathDevBounds.fTop * SK_Scalar1);
+    GrIRect bounds = GrIRect::MakeWH(pathDevBounds.width(),
+                                     pathDevBounds.height());
+
+    SkBitmap bm;
+    bm.setConfig(SkBitmap::kA8_Config, bounds.fRight, bounds.fBottom);
+    if (!bm.allocPixels()) {
+        return false;
+    }
+    sk_bzero(bm.getPixels(), bm.getSafeSize());
+
+    SkDraw  draw;
+    sk_bzero(&draw, sizeof(draw));
+    SkRasterClip rc(bounds);
+    draw.fRC    = &rc;
+    draw.fClip  = &rc.bwRgn();
+    draw.fMatrix = &matrix;
+    draw.fBitmap = &bm;
+    draw.drawPath(*pathToDraw, paint);
+
+    const GrTextureDesc desc = {
+        kNone_GrTextureFlags,
+        bounds.fRight,
+        bounds.fBottom,
+        kAlpha_8_GrPixelConfig,
+        0 // samples
+    };
+
+    tex->set(context, desc);
+    GrTexture* texture = tex->texture();
+
+    if (NULL == texture) {
+        return false;
+    }
+    SkAutoLockPixels alp(bm);
+    texture->writePixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
+                         bm.getPixels(), bm.rowBytes());
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+void draw_around_inv_path(GrDrawTarget* target,
+                          GrDrawState::StageMask stageMask,
+                          const GrIRect& clipBounds,
+                          const GrIRect& pathBounds) {
+    GrDrawTarget::AutoDeviceCoordDraw adcd(target, stageMask);
+    GrRect rect;
+    if (clipBounds.fTop < pathBounds.fTop) {
+        rect.iset(clipBounds.fLeft, clipBounds.fTop, 
+                    clipBounds.fRight, pathBounds.fTop);
+        target->drawSimpleRect(rect, NULL, stageMask);
+    }
+    if (clipBounds.fLeft < pathBounds.fLeft) {
+        rect.iset(clipBounds.fLeft, pathBounds.fTop, 
+                    pathBounds.fLeft, pathBounds.fBottom);
+        target->drawSimpleRect(rect, NULL, stageMask);
+    }
+    if (clipBounds.fRight > pathBounds.fRight) {
+        rect.iset(pathBounds.fRight, pathBounds.fTop, 
+                    clipBounds.fRight, pathBounds.fBottom);
+        target->drawSimpleRect(rect, NULL, stageMask);
+    }
+    if (clipBounds.fBottom > pathBounds.fBottom) {
+        rect.iset(clipBounds.fLeft, pathBounds.fBottom, 
+                    clipBounds.fRight, clipBounds.fBottom);
+        target->drawSimpleRect(rect, NULL, stageMask);
+    }
+}
+
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// return true on success; false on failure
 bool GrSoftwarePathRenderer::onDrawPath(const SkPath& path,
                                         GrPathFill fill,
                                         const GrVec* translate,
@@ -29,7 +211,48 @@
                                         GrDrawState::StageMask stageMask,
                                         bool antiAlias) {
 
-    // TODO: move onDrawPath routine (& its helpers) here from GrContext.cpp
+    if (NULL == fContext) {
+        return false;
+    }
+
+    GrAutoScratchTexture ast;
+    GrIRect pathBounds, clipBounds;
+    if (!get_path_and_clip_bounds(target, path, translate,
+                                  &pathBounds, &clipBounds)) {
+        return true;    // path is empty so there is nothing to do
+    }
+    if (sw_draw_path_to_mask_texture(path, pathBounds,
+                                     fill, fContext,
+                                     translate, &ast, antiAlias)) {
+        GrTexture* texture = ast.texture();
+        GrAssert(NULL != texture);
+        GrDrawTarget::AutoDeviceCoordDraw adcd(target, stageMask);
+        enum {
+            kPathMaskStage = GrPaint::kTotalStages,
+        };
+        target->drawState()->setTexture(kPathMaskStage, texture);
+        target->drawState()->sampler(kPathMaskStage)->reset();
+        GrScalar w = GrIntToScalar(pathBounds.width());
+        GrScalar h = GrIntToScalar(pathBounds.height());
+        GrRect maskRect = GrRect::MakeWH(w / texture->width(),
+                                         h / texture->height());
+        const GrRect* srcRects[GrDrawState::kNumStages] = {NULL};
+        srcRects[kPathMaskStage] = &maskRect;
+        stageMask |= 1 << kPathMaskStage;
+        GrRect dstRect = GrRect::MakeLTRB(
+                              SK_Scalar1* pathBounds.fLeft,
+                              SK_Scalar1* pathBounds.fTop,
+                              SK_Scalar1* pathBounds.fRight,
+                              SK_Scalar1* pathBounds.fBottom);
+        target->drawRect(dstRect, NULL, stageMask, srcRects, NULL);
+        target->drawState()->setTexture(kPathMaskStage, NULL);
+        if (GrIsFillInverted(fill)) {
+            draw_around_inv_path(target, stageMask,
+                                 clipBounds, pathBounds);
+        }
+        return true;
+    }
+
     return false;
 }