SkPDF: fix large-number bug

src/pdf/SkPDFDevice.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 <tuple>
 #include "SkPDFDevice.h"
 
 #include "SkAnnotation.h"
 #include "SkColor.h"
 #include "SkColorFilter.h"
 #include "SkClipStack.h"
 #include "SkData.h"
 #include "SkDraw.h"
 #include "SkGlyphCache.h"
 #include "SkPaint.h"
@@ skipping 16 matching lines @@
 #include "SkSurface.h"
 #include "SkTextFormatParams.h"
 #include "SkTemplates.h"
 #include "SkTypefacePriv.h"
 #include "SkXfermodeInterpretation.h"
 
 #define DPI_FOR_RASTER_SCALE_ONE 72
 
 // Utility functions
 
+static bool excessive_translation(const SkMatrix& m) {
+    const SkScalar kExcessiveTranslation = 8192.0f;
+    return SkScalarAbs(m.getTranslateX()) > kExcessiveTranslation
+        || SkScalarAbs(m.getTranslateY()) > kExcessiveTranslation;
+}
+
+static std::tuple<SkMatrix, SkVector> untranslate(const SkDraw& d) {
+    // https://bug.skia.org/257 If the translation is too large,
+    // PDF can't exactly represent the float values as numbers.
+    SkScalar translateX = d.fMatrix->getTranslateX() / d.fMatrix->getScaleX();
+    SkScalar translateY = d.fMatrix->getTranslateY() / d.fMatrix->getScaleY();
+    SkMatrix mat = *d.fMatrix;
+    mat.preTranslate(-translateX, -translateY);
+    SkASSERT(SkScalarAbs(mat.getTranslateX()) <= 1.0);
+    return std::make_tuple(mat, SkVector::Make(translateX, translateY));
+}
+
 // If the paint will definitely draw opaquely, replace kSrc_Mode with
 // kSrcOver_Mode.  http://crbug.com/473572
 static void replace_srcmode_on_opaque_paint(SkPaint* paint) {
     if (kSrcOver_SkXfermodeInterpretation
         == SkInterpretXfermode(*paint, false)) {
         paint->setXfermode(nullptr);
     }
 }
 
 static void emit_pdf_color(SkColor color, SkWStream* result) {
@@ skipping 740 matching lines @@
 
     if (count == 0) {
         return;
     }
 
     if (SkAnnotation* annotation = passedPaint.getAnnotation()) {
         if (handlePointAnnotation(points, count, *d.fMatrix, annotation)) {
             return;
         }
     }
+    if (excessive_translation(*d.fMatrix)) {
+        SkVector translate; SkMatrix translateMatrix;
+        std::tie(translateMatrix, translate) = untranslate(d);
+        SkDraw drawCopy(d);
+        drawCopy.fMatrix = &translateMatrix;
+        SkTArray<SkPoint> pointsCopy(points, SkToInt(count));
+        SkPoint::Offset(&pointsCopy[0], SkToInt(count), translate);
+        this->drawPoints(drawCopy, mode, count, &pointsCopy[0], srcPaint);
+        return;  // NOTE: shader behavior will be off.
+    }
 
     // SkDraw::drawPoints converts to multiple calls to fDevice->drawPath.
     // We only use this when there's a path effect because of the overhead
     // of multiple calls to setUpContentEntry it causes.
     if (passedPaint.getPathEffect()) {
         if (d.fClip->isEmpty()) {
             return;
         }
         SkDraw pointDraw(d);
         pointDraw.fDevice = this;
@@ skipping 108 matching lines @@
 }
 
 void SkPDFDevice::drawRect(const SkDraw& d,
                            const SkRect& rect,
                            const SkPaint& srcPaint) {
     SkPaint paint = srcPaint;
     replace_srcmode_on_opaque_paint(&paint);
     SkRect r = rect;
     r.sort();
 
+    if (excessive_translation(*d.fMatrix)) {
+        SkVector translate; SkMatrix translateMatrix;
+        std::tie(translateMatrix, translate) = untranslate(d);
+        SkDraw drawCopy(d);
+        drawCopy.fMatrix = &translateMatrix;
+        SkRect rectCopy = rect;
+        rectCopy.offset(translate.x(), translate.y());
+        this->drawRect(drawCopy, rectCopy, srcPaint);
+        return;  // NOTE: shader behavior will be off.
+    }
+
     if (paint.getPathEffect()) {
         if (d.fClip->isEmpty()) {
             return;
         }
         SkPath path;
         path.addRect(r);
         drawPath(d, path, paint, nullptr, true);
         return;
     }
 
@@ skipping 32 matching lines @@
     SkPath  path;
     path.addOval(oval);
     this->drawPath(draw, path, paint, nullptr, true);
 }
 
 void SkPDFDevice::drawPath(const SkDraw& d,
                            const SkPath& origPath,
                            const SkPaint& srcPaint,
                            const SkMatrix* prePathMatrix,
                            bool pathIsMutable) {
+    if (excessive_translation(*d.fMatrix)) {
+        SkVector translate; SkMatrix translateMatrix;
+        std::tie(translateMatrix, translate) = untranslate(d);
+        SkDraw drawCopy(d);
+        drawCopy.fMatrix = &translateMatrix;
+        SkPath pathCopy(origPath);
+        pathCopy.offset(translate.x(), translate.y());
+        this->drawPath(drawCopy, pathCopy, srcPaint, prePathMatrix, true);
+        return;  // NOTE: shader behavior will be off.
+    }
+
     SkPaint paint = srcPaint;
     replace_srcmode_on_opaque_paint(&paint);
     SkPath modifiedPath;
     SkPath* pathPtr = const_cast<SkPath*>(&origPath);
 
     SkMatrix matrix = *d.fMatrix;
     if (prePathMatrix) {
         if (paint.getPathEffect() || paint.getStyle() != SkPaint::kFill_Style) {
             if (!pathIsMutable) {
                 pathPtr = &modifiedPath;
@@ skipping 272 matching lines @@
             device->drawText(d, text, len, x, y, transparent);
             break;
         default:
             SkFAIL("unknown text encoding");
     }
 }
 
 
 void SkPDFDevice::drawText(const SkDraw& d, const void* text, size_t len,
                            SkScalar x, SkScalar y, const SkPaint& srcPaint) {
+    if (excessive_translation(*d.fMatrix)) {
+        SkVector translate; SkMatrix translateMatrix;
+        std::tie(translateMatrix, translate) = untranslate(d);
+        SkDraw drawCopy(d);
+        drawCopy.fMatrix = &translateMatrix;
+        this->drawText(drawCopy, text, len, x + translate.x(),
+                       y + translate.y(), srcPaint);
+        return;  // NOTE: shader behavior will be off.
+    }
+
     if (!SkPDFFont::CanEmbedTypeface(srcPaint.getTypeface(), fCanon)) {
         // https://bug.skia.org/3866
         SkPath path;
         srcPaint.getTextPath(text, len, x, y, &path);
         this->drawPath(d, path, srcPaint, &SkMatrix::I(), true);
         // Draw text transparently to make it copyable/searchable/accessable.
         draw_transparent_text(this, d, text, len, x, y, srcPaint);
         return;
     }
     SkPaint paint = srcPaint;
@@ skipping 41 matching lines @@
         content.entry()->fContent.writeText(encodedString.c_str());
         consumedGlyphCount += availableGlyphs;
         content.entry()->fContent.writeText(" Tj\n");
     }
     content.entry()->fContent.writeText("ET\n");
 }
 
 void SkPDFDevice::drawPosText(const SkDraw& d, const void* text, size_t len,
                               const SkScalar pos[], int scalarsPerPos,
                               const SkPoint& offset, const SkPaint& srcPaint) {
+    if (excessive_translation(*d.fMatrix)) {
+        SkVector translate; SkMatrix translateMatrix;
+        std::tie(translateMatrix, translate) = untranslate(d);
+        SkDraw drawCopy(d);
+        drawCopy.fMatrix = &translateMatrix;
+        SkPoint offsetCopy = offset;
+        SkPoint::Offset(&offsetCopy, 1, translate.x(), translate.y());
+        this->drawPosText(drawCopy, text, len, pos, scalarsPerPos, offsetCopy,
+                          srcPaint);
+        return;  // NOTE: shader behavior will be off.
+    }
+
     if (!SkPDFFont::CanEmbedTypeface(srcPaint.getTypeface(), fCanon)) {
         const SkPoint* positions = reinterpret_cast<const SkPoint*>(pos);
         SkAutoTMalloc<SkPoint> positionsBuffer;
         if (2 != scalarsPerPos) {
             int glyphCount = srcPaint.textToGlyphs(text, len, NULL);
             positionsBuffer.reset(glyphCount);
             for (int  i = 0; i < glyphCount; ++i) {
                 positionsBuffer[i].set(pos[i], 0.0f);
             }
             positions = &positionsBuffer[0];
@@ skipping 1016 matching lines @@
     if (!pdfimage) {
         pdfimage.reset(SkPDFCreateBitmapObject(image));
         if (!pdfimage) {
             return;
         }
         fCanon->addPDFBitmap(image->uniqueID(), pdfimage);
     }
     SkPDFUtils::DrawFormXObject(this->addXObjectResource(pdfimage.get()),
                                 &content.entry()->fContent);
 }