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-rw-r--r--src/core/SkEdge.cpp14
-rw-r--r--src/core/SkEdge.h2
-rw-r--r--src/core/SkQuadClipper.cpp92
-rw-r--r--src/core/SkQuadClipper.h41
-rw-r--r--src/core/SkScan_Path.cpp23
-rw-r--r--src/core/core_files.mk1
6 files changed, 155 insertions, 18 deletions
diff --git a/src/core/SkEdge.cpp b/src/core/SkEdge.cpp
index 6efe1bad39..f790d02a8b 100644
--- a/src/core/SkEdge.cpp
+++ b/src/core/SkEdge.cpp
@@ -173,7 +173,7 @@ static inline int diff_to_shift(SkFDot6 dx, SkFDot6 dy)
return (32 - SkCLZ(dist)) >> 1;
}
-int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], const SkIRect* clip, int shift)
+int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], int shift)
{
SkFDot6 x0, y0, x1, y1, x2, y2;
@@ -212,9 +212,6 @@ int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], const SkIRect* clip, int
// are we a zero-height quad (line)?
if (top == bot)
return 0;
- // are we completely above or below the clip?
- if (clip && (top >= clip->fBottom || bot <= clip->fTop))
- return 0;
// compute number of steps needed (1 << shift)
{
@@ -252,15 +249,6 @@ int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], const SkIRect* clip, int
fQLastX = SkFDot6ToFixed(x2);
fQLastY = SkFDot6ToFixed(y2);
- if (clip)
- {
- do {
- for (;!this->updateQuadratic();)
- ;
- } while (!this->intersectsClip(*clip));
- this->chopLineWithClip(*clip);
- return 1;
- }
return this->updateQuadratic();
}
diff --git a/src/core/SkEdge.h b/src/core/SkEdge.h
index 5b0cc75d4c..eb50a4245a 100644
--- a/src/core/SkEdge.h
+++ b/src/core/SkEdge.h
@@ -75,7 +75,7 @@ struct SkQuadraticEdge : public SkEdge {
SkFixed fQDDx, fQDDy;
SkFixed fQLastX, fQLastY;
- int setQuadratic(const SkPoint pts[3], const SkIRect* clip, int shiftUp);
+ int setQuadratic(const SkPoint pts[3], int shiftUp);
int updateQuadratic();
};
diff --git a/src/core/SkQuadClipper.cpp b/src/core/SkQuadClipper.cpp
new file mode 100644
index 0000000000..c6add69745
--- /dev/null
+++ b/src/core/SkQuadClipper.cpp
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SkQuadClipper.h"
+#include "SkGeometry.h"
+
+static bool chopMonoQuadAtY(SkPoint pts[3], SkScalar y, SkScalar* t) {
+ /* Solve F(t) = y where F(t) := [0](1-t)^2 + 2[1]t(1-t) + [2]t^2
+ * We solve for t, using quadratic equation, hence we have to rearrange
+ * our cooefficents to look like At^2 + Bt + C
+ */
+ SkScalar A = pts[0].fY - pts[1].fY - pts[1].fY + pts[2].fY;
+ SkScalar B = 2*(pts[1].fY - pts[0].fY);
+ SkScalar C = pts[0].fY - y;
+
+ SkScalar roots[2]; // we only expect one, but make room for 2 for safety
+ int count = SkFindUnitQuadRoots(A, B, C, roots);
+ if (count) {
+ *t = roots[0];
+ return true;
+ }
+ return false;
+}
+
+SkQuadClipper::SkQuadClipper() {}
+
+void SkQuadClipper::setClip(const SkIRect& clip) {
+ // conver to scalars, since that's where we'll see the points
+ fClip.set(clip);
+}
+
+/* If we somehow returned the fact that we had to flip the pts in Y, we could
+ communicate that to setQuadratic, and then avoid having to flip it back
+ here (only to have setQuadratic do the flip again)
+ */
+bool SkQuadClipper::clipQuad(const SkPoint srcPts[3], SkPoint dst[3]) {
+ bool reverse;
+
+ // we need the data to be monotonically descending in Y
+ if (srcPts[0].fY > srcPts[2].fY) {
+ dst[0] = srcPts[2];
+ dst[1] = srcPts[1];
+ dst[2] = srcPts[0];
+ reverse = true;
+ } else {
+ memcpy(dst, srcPts, 3 * sizeof(SkPoint));
+ reverse = false;
+ }
+
+ // are we completely above or below
+ const SkScalar ctop = fClip.fTop;
+ const SkScalar cbot = fClip.fBottom;
+ if (dst[2].fY <= ctop || dst[0].fY >= cbot) {
+ return false;
+ }
+
+ SkScalar t;
+ SkPoint tmp[5]; // for SkChopQuadAt
+
+ // are we partially above
+ if (dst[0].fY < ctop && chopMonoQuadAtY(dst, ctop, &t)) {
+ SkChopQuadAt(dst, tmp, t);
+ dst[0] = tmp[2];
+ dst[1] = tmp[3];
+ }
+
+ // are we partially below
+ if (dst[2].fY > cbot && chopMonoQuadAtY(dst, cbot, &t)) {
+ SkChopQuadAt(dst, tmp, t);
+ dst[1] = tmp[1];
+ dst[2] = tmp[2];
+ }
+
+ if (reverse) {
+ SkTSwap<SkPoint>(dst[0], dst[2]);
+ }
+ return true;
+}
+
diff --git a/src/core/SkQuadClipper.h b/src/core/SkQuadClipper.h
new file mode 100644
index 0000000000..fcb230f7fa
--- /dev/null
+++ b/src/core/SkQuadClipper.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SkQuadClipper_DEFINED
+#define SkQuadClipper_DEFINED
+
+#include "SkPoint.h"
+#include "SkRect.h"
+
+/** This class is initialized with a clip rectangle, and then can be fed quads,
+ which must already be monotonic in Y.
+
+ In the future, it might return a series of segments, allowing it to clip
+ also in X, to ensure that all segments fit in a finite coordinate system.
+ */
+class SkQuadClipper {
+public:
+ SkQuadClipper();
+
+ void setClip(const SkIRect& clip);
+
+ bool clipQuad(const SkPoint src[3], SkPoint dst[3]);
+
+private:
+ SkRect fClip;
+};
+
+#endif
diff --git a/src/core/SkScan_Path.cpp b/src/core/SkScan_Path.cpp
index d8f779a32c..fcf1530c80 100644
--- a/src/core/SkScan_Path.cpp
+++ b/src/core/SkScan_Path.cpp
@@ -20,6 +20,7 @@
#include "SkEdge.h"
#include "SkGeometry.h"
#include "SkPath.h"
+#include "SkQuadClipper.h"
#include "SkRegion.h"
#include "SkTemplates.h"
@@ -306,6 +307,14 @@ static int build_edges(SkEdge edge[], const SkPath& path,
SkPath::Iter iter(path, true);
SkPoint pts[4];
SkPath::Verb verb;
+
+ SkQuadClipper qclipper;
+ if (clipRect) {
+ SkIRect r;
+ r.set(clipRect->fLeft >> shiftUp, clipRect->fTop >> shiftUp,
+ clipRect->fRight >> shiftUp, clipRect->fBottom >> shiftUp);
+ qclipper.setClip(r);
+ }
while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
switch (verb) {
@@ -316,17 +325,23 @@ static int build_edges(SkEdge edge[], const SkPath& path,
}
break;
case SkPath::kQuad_Verb: {
- SkPoint tmp[5];
+ SkPoint tmp[5], clippedPts[3];
SkPoint* p = tmp;
int count = SkChopQuadAtYExtrema(pts, tmp);
do {
- if (((SkQuadraticEdge*)edge)->setQuadratic(p, clipRect,
- shiftUp))
- {
+ const SkPoint* qpts = p;
+ if (clipRect) {
+ if (!qclipper.clipQuad(p, clippedPts)) {
+ goto NEXT_CHOPPED_QUAD;
+ }
+ qpts = clippedPts;
+ }
+ if (((SkQuadraticEdge*)edge)->setQuadratic(qpts, shiftUp)) {
*list++ = edge;
edge = (SkEdge*)((char*)edge + sizeof(SkQuadraticEdge));
}
+ NEXT_CHOPPED_QUAD:
p += 2;
} while (--count >= 0);
break;
diff --git a/src/core/core_files.mk b/src/core/core_files.mk
index 93a68ae8b8..0200242239 100644
--- a/src/core/core_files.mk
+++ b/src/core/core_files.mk
@@ -58,6 +58,7 @@ SOURCE := \
SkPixelRef.cpp \
SkPoint.cpp \
SkPtrRecorder.cpp \
+ SkQuadClipper.cpp \
SkRasterizer.cpp \
SkRect.cpp \
SkRefCnt.cpp \
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-31 16:08:22 +0000