add TrimPathEffect

Bug: skia:
Change-Id: I453fb81ded4435b33567e9c8a6f3abe9535d687f
Reviewed-on: https://skia-review.googlesource.com/112820
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

1 files changed, 63 insertions, 0 deletions

diff --git a/src/effects/SkTrimPathEffect.cpp b/src/effects/SkTrimPathEffect.cpp
new file mode 100644
index 0000000000..beaa36e17d
--- /dev/null
+++ b/src/effects/SkTrimPathEffect.cpp
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPathMeasure.h"
+#include "SkTrimPathEffect.h"
+#include "SkTrimPE.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+
+SkTrimPE::SkTrimPE(SkScalar startT, SkScalar stopT) : fStartT(startT), fStopT(stopT) {
+    SkASSERT(startT >= 0 && startT <= 1);
+    SkASSERT(stopT >= 0 && stopT <= 1);
+    SkASSERT(startT != stopT);
+}
+
+bool SkTrimPE::filterPath(SkPath* dst, const SkPath& src, SkStrokeRec* rec,
+                            const SkRect* cullRect) const {
+    SkPathMeasure meas(src, false);
+    SkScalar length = meas.getLength();
+
+    if (fStartT < fStopT) {
+        meas.getSegment(fStartT * length, fStopT * length, dst, true);
+    } else {
+        meas.getSegment(0, fStopT * length, dst, true);
+        meas.getSegment(fStartT * length, length, dst, true);
+    }
+    return true;
+}
+
+void SkTrimPE::flatten(SkWriteBuffer& buffer) const {
+    buffer.writeScalar(fStartT);
+    buffer.writeScalar(fStopT);
+}
+
+sk_sp<SkFlattenable> SkTrimPE::CreateProc(SkReadBuffer& buffer) {
+    SkScalar start = buffer.readScalar();
+    SkScalar stop = buffer.readScalar();
+    return SkTrimPathEffect::Make(start, stop);
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkTrimPE::toString(SkString* str) const {
+    str->appendf("SkTrimPathEffect: (%g %g)", fStartT, fStopT);
+}
+#endif
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkPathEffect> SkTrimPathEffect::Make(SkScalar startT, SkScalar stopT) {
+    if (!SkScalarsAreFinite(startT, stopT)) {
+        return nullptr;
+    }
+    startT = SkTPin(startT, 0.f, 1.f);
+    stopT  = SkTPin(stopT,  0.f, 1.f);
+    if (startT == stopT) {
+        return nullptr;
+    }
+    return sk_sp<SkPathEffect>(new SkTrimPE(startT, stopT));
+}