Attempt to combine text runs positioned with setTextMatrix

src/core/evaluator.js

@@ -1396,7 +1396,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
           textState = stateManager.state;
           var fn = operation.fn;
           args = operation.args;
-          var advance;
+          var advance, diff;
 
           switch (fn | 0) {
             case OPS.setFont:
@@ -1429,7 +1429,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
                   (args[0] - textContentItem.lastAdvanceWidth);
                 textContentItem.height +=
                   (args[1] - textContentItem.lastAdvanceHeight);
-                var diff = (args[0] - textContentItem.lastAdvanceWidth) -
+                diff = (args[0] - textContentItem.lastAdvanceWidth) -
                        (args[1] - textContentItem.lastAdvanceHeight);
                 addFakeSpaces(diff, textContentItem.str);
                 break;
@@ -1450,6 +1450,24 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
               textState.carriageReturn();
               break;
             case OPS.setTextMatrix:
+              // Optimization to treat same line movement as advance.
+              advance = textState.calcTextLineMatrixAdvance(
+                args[0], args[1], args[2], args[3], args[4], args[5]);
+              if (advance !== null && textContentItem.initialized &&
+                  advance.value > 0 &&
+                  advance.value <= textContentItem.fakeMultiSpaceMax) {
+                textState.translateTextLineMatrix(advance.width,
+                                                  advance.height);
+                textContentItem.width +=
+                  (advance.width - textContentItem.lastAdvanceWidth);
+                textContentItem.height +=
+                  (advance.height - textContentItem.lastAdvanceHeight);
+                diff = (advance.width - textContentItem.lastAdvanceWidth) -
+                       (advance.height - textContentItem.lastAdvanceHeight);
+                addFakeSpaces(diff, textContentItem.str);
+                break;
+              }
+
               flushTextContentItem();
               textState.setTextMatrix(args[0], args[1], args[2], args[3],
                 args[4], args[5]);
@@ -2547,6 +2565,30 @@ var TextState = (function TextStateClosure() {
       m[4] = m[0] * x + m[2] * y + m[4];
       m[5] = m[1] * x + m[3] * y + m[5];
     },
+    calcTextLineMatrixAdvance:
+        function TextState_calcTextLineMatrixAdvance(a, b, c, d, e, f) {
+      var font = this.font;
+      if (!font) {
+        return null;
+      }
+      var m = this.textLineMatrix;
+      if (!(a === m[0] && b === m[1] && c === m[2] && d === m[3])) {
+        return null;
+      }
+      var txDiff = e - m[4], tyDiff = f - m[5];
+      if ((font.vertical && txDiff !== 0) || (!font.vertical && tyDiff !== 0)) {
+        return null;
+      }
+      var tx, ty, denominator = a * d - b * c;
+      if (font.vertical) {
+        tx = -tyDiff * c / denominator;
+        ty = tyDiff * a / denominator;
+      } else {
+        tx = txDiff * d / denominator;
+        ty = -txDiff * b / denominator;
+      }
+      return { width: tx, height: ty, value: (font.vertical ? ty : tx), };
+    },
     calcRenderMatrix: function TextState_calcRendeMatrix(ctm) {
       // 9.4.4 Text Space Details
       var tsm = [this.fontSize * this.textHScale, 0,

test/pdfs/.gitignore

@@ -20,6 +20,7 @@
 !issue6204.pdf
 !issue6782.pdf
 !issue6961.pdf
+!issue6962.pdf
 !issue7020.pdf
 !issue7101.pdf
 !issue7115.pdf

test/test_manifest.json

@@ -1111,6 +1111,13 @@
        "type": "eq",
        "about": "Please note that this file currently renders incorrectly."
     },
+    {  "id": "issue6962",
+       "file": "pdfs/issue6962.pdf",
+       "md5": "d40e871ecca68baf93114bd28c782148",
+       "rounds": 1,
+       "link": false,
+       "type": "text"
+    },
     {  "id": "issue5644",
        "file": "pdfs/issue5644.pdf",
        "md5": "6f9313c5043b3ecb0ab2df321d3e1847",