Merge pull request #21061 from calixteman/pattern_perf

Avoid as much as possible to have intermediate canvases

src/core/evaluator.js

@@ -29,6 +29,7 @@ import {
   Util,
   warn,
 } from "../shared/util.js";
+import { CheckedOperatorList, OperatorList } from "./operator_list.js";
 import { CMapFactory, IdentityCMap } from "./cmap.js";
 import { Cmd, Dict, EOF, isName, Name, Ref, RefSet } from "./primitives.js";
 import {
@@ -85,7 +86,6 @@ import { getGlyphsUnicode } from "./glyphlist.js";
 import { getMetrics } from "./metrics.js";
 import { getUnicodeForGlyph } from "./unicode.js";
 import { MurmurHash3_64 } from "../shared/murmurhash3.js";
-import { OperatorList } from "./operator_list.js";
 import { PDFImage } from "./image.js";
 import { Stream } from "./stream.js";
 
@@ -501,7 +501,17 @@ class PartialEvaluator {
     if (optionalContent !== undefined) {
       operatorList.addOp(OPS.beginMarkedContentProps, ["OC", optionalContent]);
     }
+
     const group = dict.get("Group");
+    let newOpList;
+
+    // If it's a group, a new canvas will be created that is the size of the
+    // bounding box and translated to the correct position so we don't need to
+    // apply the bounding box to it.
+    const f32matrix = matrix && new Float32Array(matrix);
+    const args = [f32matrix, (!group && f32bbox) || null];
+    const localResources = dict.get("Resources");
+
     if (group) {
       groupOptions = {
         matrix,
@@ -509,6 +519,7 @@ class PartialEvaluator {
         smask,
         isolated: false,
         knockout: false,
+        needsIsolation: false,
       };
 
       const groupSubtype = group.get("S");
@@ -532,30 +543,30 @@ class PartialEvaluator {
         smask.backdrop = colorSpace.getRgbHex(smask.backdrop, 0);
       }
 
-      operatorList.addOp(OPS.beginGroup, [groupOptions]);
+      newOpList = new CheckedOperatorList();
+    } else {
+      newOpList = operatorList;
+      operatorList.addOp(OPS.paintFormXObjectBegin, args);
     }
 
-    // If it's a group, a new canvas will be created that is the size of the
-    // bounding box and translated to the correct position so we don't need to
-    // apply the bounding box to it.
-    const f32matrix = matrix && new Float32Array(matrix);
-    const args = [f32matrix, (!group && f32bbox) || null];
-    operatorList.addOp(OPS.paintFormXObjectBegin, args);
-
-    const localResources = dict.get("Resources");
-
     await this.getOperatorList({
       stream: xobj,
       task,
       resources: localResources instanceof Dict ? localResources : resources,
-      operatorList,
+      operatorList: newOpList,
       initialState,
       prevRefs: seenRefs,
     });
-    operatorList.addOp(OPS.paintFormXObjectEnd, []);
 
     if (group) {
+      groupOptions.needsIsolation = newOpList.needsIsolation || !!smask;
+      operatorList.addOp(OPS.beginGroup, [groupOptions]);
+      operatorList.addOp(OPS.paintFormXObjectBegin, args);
+      operatorList.addOpList(newOpList);
+      operatorList.addOp(OPS.paintFormXObjectEnd, []);
       operatorList.addOp(OPS.endGroup, [groupOptions]);
+    } else {
+      operatorList.addOp(OPS.paintFormXObjectEnd, []);
     }
 
     if (optionalContent !== undefined) {
@@ -972,7 +983,7 @@ class PartialEvaluator {
     localTilingPatternCache
   ) {
     // Create an IR of the pattern code.
-    const tilingOpList = new OperatorList();
+    const tilingOpList = new CheckedOperatorList();
     // Merge the available resources, to prevent issues when the patternDict
     // is missing some /Resources entries (fixes issue6541.pdf).
     const patternResources = Dict.merge({
@@ -988,10 +999,12 @@ class PartialEvaluator {
     })
       .then(function () {
         const operatorListIR = tilingOpList.getIR();
+        const { needsIsolation } = tilingOpList;
         const tilingPatternIR = getTilingPatternIR(
           operatorListIR,
           patternDict,
-          color
+          color,
+          needsIsolation
         );
         // Add the dependencies to the parent operator list so they are
         // resolved before the sub operator list is executed synchronously.
@@ -1001,6 +1014,7 @@ class PartialEvaluator {
         if (patternDict.objId) {
           localTilingPatternCache.set(/* name = */ null, patternDict.objId, {
             operatorListIR,
+            needsIsolation,
             dict: patternDict,
           });
         }
@@ -1578,7 +1592,8 @@ class PartialEvaluator {
           const tilingPatternIR = getTilingPatternIR(
             localTilingPattern.operatorListIR,
             localTilingPattern.dict,
-            color
+            color,
+            localTilingPattern.needsIsolation
           );
           operatorList.addOp(fn, tilingPatternIR);
           return undefined;

src/core/operator_list.js

@@ -822,4 +822,35 @@ class OperatorList {
   }
 }
 
-export { OperatorList };
+/**
+ * A subclass of OperatorList that checks whether added group or pattern
+ * operations require being drawn in isolation (i.e. on a separate canvas).
+ * A group/pattern needs isolation when it uses non-default compositing
+ * (blend mode) or a soft mask. The result is exposed via `needsIsolation`.
+ */
+class CheckedOperatorList extends OperatorList {
+  needsIsolation = false;
+
+  addOp(fn, args) {
+    if (!this.needsIsolation) {
+      if (fn === OPS.beginGroup) {
+        // Propagate isolation only if the nested group itself needs it.
+        this.needsIsolation = args[0].needsIsolation;
+      } else if (fn === OPS.setGState) {
+        for (const [key, val] of args[0]) {
+          if (key === "BM" && val !== "source-over") {
+            this.needsIsolation = true;
+            break;
+          }
+          if (key === "SMask" && val !== false) {
+            this.needsIsolation = true;
+            break;
+          }
+        }
+      }
+    }
+    super.addOp(fn, args);
+  }
+}
+
+export { CheckedOperatorList, OperatorList };

src/core/pattern.js

@@ -1139,7 +1139,7 @@ class DummyShading extends BaseShading {
   }
 }
 
-function getTilingPatternIR(operatorList, dict, color) {
+function getTilingPatternIR(operatorList, dict, color, needsIsolation = true) {
   const matrix = lookupMatrix(dict.getArray("Matrix"), IDENTITY_MATRIX);
   const bbox = lookupNormalRect(dict.getArray("BBox"), null);
   // Ensure that the pattern has a non-zero width and height, to prevent errors
@@ -1174,6 +1174,7 @@ function getTilingPatternIR(operatorList, dict, color) {
     ystep,
     paintType,
     tilingType,
+    needsIsolation,
   ];
 }
 

src/display/canvas.js

@@ -2608,7 +2608,8 @@ class CanvasGraphics {
     this.save(opIdx);
     // If there's an active soft mask we don't want it enabled for the group, so
     // clear it out. The mask and suspended canvas will be restored in endGroup.
-    if (this.inSMaskMode) {
+    const { inSMaskMode } = this;
+    if (inSMaskMode) {
       this.endSMaskMode();
       this.current.activeSMask = null;
     }
@@ -2637,6 +2638,28 @@ class CanvasGraphics {
       warn("Knockout groups not supported.");
     }
 
+    if (
+      !group.needsIsolation &&
+      currentCtx.globalAlpha === 1 &&
+      currentCtx.globalCompositeOperation === "source-over" &&
+      !inSMaskMode
+    ) {
+      if (group.bbox) {
+        let clip = new Path2D();
+        const [x0, y0, x1, y1] = group.bbox;
+        clip.rect(x0, y0, x1 - x0, y1 - y0);
+        if (group.matrix) {
+          const path = new Path2D();
+          path.addPath(clip, new DOMMatrix(group.matrix));
+          clip = path;
+        }
+        currentCtx.clip(clip);
+      }
+      this.groupStack.push(null); // null = no intermediate canvas
+      this.groupLevel++;
+      return;
+    }
+
     const currentTransform = getCurrentTransform(currentCtx);
     if (group.matrix) {
       currentCtx.transform(...group.matrix);
@@ -2756,6 +2779,12 @@ class CanvasGraphics {
     this.groupLevel--;
     const groupCtx = this.ctx;
     const ctx = this.groupStack.pop();
+    if (ctx === null) {
+      // Simple group: content was drawn directly on the parent canvas.
+      this.restore(opIdx);
+      return;
+    }
+
     this.ctx = ctx;
     // Turn off image smoothing to avoid sub pixel interpolation which can
     // look kind of blurry for some pdfs.

src/display/pattern_helper.js

@@ -614,6 +614,7 @@ class TilingPattern {
     this.ystep = IR[6];
     this.paintType = IR[7];
     this.tilingType = IR[8];
+    this.needsIsolation = IR[9] ?? true;
     this.ctx = ctx;
     this.canvasGraphicsFactory = canvasGraphicsFactory;
     this.baseTransform = baseTransform;
@@ -702,23 +703,6 @@ class TilingPattern {
   // Draws a single tile directly onto owner, clipped to path.
   drawPattern(owner, path, useEOFill = false, [n, m], opIdx) {
     const [x0, y0, x1, y1] = this.bbox;
-    const bboxWidth = x1 - x0;
-    const bboxHeight = y1 - y0;
-
-    const [combinedScaleX, combinedScaleY] = this._getCombinedScales();
-    const dimx = this.getSizeAndScale(
-      bboxWidth,
-      this.ctx.canvas.width,
-      combinedScaleX
-    );
-    const dimy = this.getSizeAndScale(
-      bboxHeight,
-      this.ctx.canvas.height,
-      combinedScaleY
-    );
-
-    // Isolate blend modes from the main canvas.
-    const tmpCanvas = this._renderTileCanvas(owner, opIdx, dimx, dimy);
 
     owner.save();
     if (useEOFill) {
@@ -730,9 +714,39 @@ class TilingPattern {
     // by setTransform.
     owner.ctx.setTransform(...this.patternBaseMatrix);
     owner.ctx.translate(n * this.xstep, m * this.ystep);
-    owner.ctx.drawImage(tmpCanvas.canvas, x0, y0, bboxWidth, bboxHeight);
+    if (
+      this.needsIsolation ||
+      owner.ctx.globalAlpha !== 1 ||
+      owner.ctx.globalCompositeOperation !== "source-over" ||
+      owner.inSMaskMode
+    ) {
+      const bboxWidth = x1 - x0;
+      const bboxHeight = y1 - y0;
+      const [combinedScaleX, combinedScaleY] = this._getCombinedScales();
+      const dimx = this.getSizeAndScale(
+        bboxWidth,
+        this.ctx.canvas.width,
+        combinedScaleX
+      );
+      const dimy = this.getSizeAndScale(
+        bboxHeight,
+        this.ctx.canvas.height,
+        combinedScaleY
+      );
+      // Isolate blend modes from the main canvas.
+      const tmpCanvas = this._renderTileCanvas(owner, opIdx, dimx, dimy);
+      owner.ctx.drawImage(tmpCanvas.canvas, x0, y0, bboxWidth, bboxHeight);
+      owner.canvasFactory.destroy(tmpCanvas);
+    } else {
+      // No blend modes or transparency: render the tile directly onto owner.
+      this.setFillAndStrokeStyleToContext(owner, this.paintType, this.color);
+      this.clipBbox(owner, x0, y0, x1, y1);
+      owner.baseTransformStack.push(owner.baseTransform);
+      owner.baseTransform = getCurrentTransform(owner.ctx);
+      owner.executeOperatorList(this.operatorList);
+      owner.baseTransform = owner.baseTransformStack.pop();
+    }
 
-    owner.canvasFactory.destroy(tmpCanvas);
     owner.restore();
   }
 
@@ -892,14 +906,15 @@ class TilingPattern {
   clipBbox(graphics, x0, y0, x1, y1) {
     const bboxWidth = x1 - x0;
     const bboxHeight = y1 - y0;
-    graphics.ctx.rect(x0, y0, bboxWidth, bboxHeight);
+    const clip = new Path2D();
+    clip.rect(x0, y0, bboxWidth, bboxHeight);
     Util.axialAlignedBoundingBox(
       [x0, y0, x1, y1],
       getCurrentTransform(graphics.ctx),
       graphics.current.minMax
     );
-    graphics.clip();
+    graphics.ctx.clip(clip);
-    graphics.endPath();
+    graphics.current.updateClipFromPath();
   }
 
   setFillAndStrokeStyleToContext(graphics, paintType, color) {