Make GrBatchAtlas robust against attempts to add large rects.

tests/DFPathRendererTest.cpp

+/*
+ * Copyright 2016 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"
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+#include "GrTest.h"
+#include "batches/GrAADistanceFieldPathRenderer.h"
+#include "SkPath.h"
+
+// This test case including path coords and matrix taken from crbug.com/627443.
+// Because of inaccuracies in large floating point values this causes the
+// the path renderer to attempt to add a path DF to its atlas that is larger
+// than the plot size which used to crash rather than fail gracefully.
+static void test_far_from_origin(GrDrawContext* drawContext, GrPathRenderer* pr,
+                                 GrResourceProvider* rp) {
+    SkPath path;
+    path.lineTo(49.0255089839f, 0.473541f);
+    static constexpr SkScalar mvals[] = {14.0348252854f, 2.13026182736f,
+                                         13.6122547187f, 118.309922702f,
+                                         1912337682.09f, 2105391889.87f};
+    SkMatrix matrix;
+    matrix.setAffine(mvals);
+    SkMatrix inverse;
+    SkAssertResult(matrix.invert(&inverse));
+    path.transform(inverse);
+
+    SkStrokeRec rec(SkStrokeRec::kFill_InitStyle);
+    rec.setStrokeStyle(1.f);
+    rec.setStrokeParams(SkPaint::kRound_Cap, SkPaint::kRound_Join, 1.f);
+    GrStyle style(rec, nullptr);
+
+    GrShape shape(path, style);
+    shape = shape.applyStyle(GrStyle::Apply::kPathEffectAndStrokeRec, 1.f);
+
+    GrPaint paint;
+    paint.setXPFactory(GrPorterDuffXPFactory::Make(SkXfermode::kSrc_Mode));
+
+    GrNoClip noClip;
+    GrPathRenderer::DrawPathArgs args;
+    args.fPaint = &paint;
+    args.fUserStencilSettings = &GrUserStencilSettings::kUnused;
+    args.fDrawContext = drawContext;
+    args.fClip = &noClip;
+    args.fResourceProvider = rp;
+    args.fViewMatrix = &matrix;
+    args.fShape = &shape;
+    args.fAntiAlias = true;
+
+    pr->drawPath(args);
+}
+
+DEF_GPUTEST_FOR_ALL_GL_CONTEXTS(AADistanceFieldPathRenderer, reporter, ctxInfo) {
+    // The DF PR only works with contexts that support derivatives
+    if (!ctxInfo.grContext()->caps()->shaderCaps()->shaderDerivativeSupport()) {
+        return;
+    }
+    sk_sp<GrDrawContext> drawContext(ctxInfo.grContext()->newDrawContext(SkBackingFit::kApprox,
+                                                                         800, 800,
+                                                                         kSkia8888_GrPixelConfig,
+                                                                         0,
+                                                                         kTopLeft_GrSurfaceOrigin));
+    if (!drawContext) {
+        return;
+    }
+
+    GrAADistanceFieldPathRenderer dfpr;
+    GrTestTarget tt;
+    ctxInfo.grContext()->getTestTarget(&tt, drawContext);
+    GrResourceProvider* rp = tt.resourceProvider();
+
+    test_far_from_origin(drawContext.get(), &dfpr, rp);
+    ctxInfo.grContext()->flush();
+}
+#endif