Use positive dimensions for text chunks in the text layer (issue #14415).

Author: calixteman

src/core/evaluator.js

@@ -2367,8 +2367,8 @@ class PartialEvaluator {
       return {
         str,
         dir: bidiResult.dir,
-        width: textChunk.totalWidth,
-        height: textChunk.totalHeight,
+        width: Math.abs(textChunk.totalWidth),
+        height: Math.abs(textChunk.totalHeight),
         transform: textChunk.transform,
         fontName: textChunk.fontName,
         hasEOL: textChunk.hasEOL,
@@ -2459,7 +2459,11 @@ class PartialEvaluator {
       if (textState.font.vertical) {
         const advanceY = (lastPosY - posY) / textContentItem.textAdvanceScale;
         const advanceX = posX - lastPosX;
-        if (advanceY < textContentItem.negativeSpaceMax) {
+
+        // When the total height of the current chunk is negative
+        // then we're writing from bottom to top.
+        const textOrientation = Math.sign(textContentItem.height);
+        if (advanceY < textOrientation * textContentItem.negativeSpaceMax) {
           if (
             Math.abs(advanceX) >
             0.5 * textContentItem.width /* not the same column */
@@ -2476,15 +2480,21 @@ class PartialEvaluator {
           appendEOL();
           return;
         }
-        if (advanceY <= textContentItem.trackingSpaceMin) {
+        if (advanceY <= textOrientation * textContentItem.trackingSpaceMin) {
           textContentItem.height += advanceY;
-        } else if (!addFakeSpaces(advanceY, textContentItem.prevTransform)) {
+        } else if (
+          !addFakeSpaces(
+            advanceY,
+            textContentItem.prevTransform,
+            textOrientation
+          )
+        ) {
           if (textContentItem.str.length === 0) {
             textContent.items.push({
               str: " ",
               dir: "ltr",
               width: 0,
-              height: advanceY,
+              height: Math.abs(advanceY),
               transform: textContentItem.prevTransform,
               fontName: textContentItem.fontName,
               hasEOL: false,
@@ -2499,7 +2509,11 @@ class PartialEvaluator {
 
       const advanceX = (posX - lastPosX) / textContentItem.textAdvanceScale;
       const advanceY = posY - lastPosY;
-      if (advanceX < textContentItem.negativeSpaceMax) {
+
+      // When the total width of the current chunk is negative
+      // then we're writing from right to left.
+      const textOrientation = Math.sign(textContentItem.width);
+      if (advanceX < textOrientation * textContentItem.negativeSpaceMax) {
         if (
           Math.abs(advanceY) >
           0.5 * textContentItem.height /* not the same line */
@@ -2516,14 +2530,16 @@ class PartialEvaluator {
         return;
       }
 
-      if (advanceX <= textContentItem.trackingSpaceMin) {
+      if (advanceX <= textOrientation * textContentItem.trackingSpaceMin) {
         textContentItem.width += advanceX;
-      } else if (!addFakeSpaces(advanceX, textContentItem.prevTransform)) {
+      } else if (
+        !addFakeSpaces(advanceX, textContentItem.prevTransform, textOrientation)
+      ) {
         if (textContentItem.str.length === 0) {
           textContent.items.push({
             str: " ",
             dir: "ltr",
-            width: advanceX,
+            width: Math.abs(advanceX),
             height: 0,
             transform: textContentItem.prevTransform,
             fontName: textContentItem.fontName,
@@ -2652,10 +2668,10 @@ class PartialEvaluator {
       }
     }
 
-    function addFakeSpaces(width, transf) {
+    function addFakeSpaces(width, transf, textOrientation) {
       if (
-        textContentItem.spaceInFlowMin <= width &&
-        width <= textContentItem.spaceInFlowMax
+        textOrientation * textContentItem.spaceInFlowMin <= width &&
+        width <= textOrientation * textContentItem.spaceInFlowMax
       ) {
         if (textContentItem.initialized) {
           textContentItem.str.push(" ");
@@ -2677,8 +2693,8 @@ class PartialEvaluator {
         // TODO: check if using the orientation from last chunk is
         // better or not.
         dir: "ltr",
-        width,
-        height,
+        width: Math.abs(width),
+        height: Math.abs(height),
         transform: transf || getCurrentTextTransform(),
         fontName,
         hasEOL: false,

test/pdfs/.gitignore

@@ -500,3 +500,4 @@
 !poppler-937-0-fuzzed.pdf
 !PDFBOX-3148-2-fuzzed.pdf
 !poppler-90-0-fuzzed.pdf
+!issue14415.pdf

test/pdfs/issue14415.pdf

@@ -6191,5 +6191,10 @@
       "link": true,
       "rounds": 1,
       "type": "eq"
-    }
+    },
+    { "id": "issue14415",
+      "file": "pdfs/issue14415.pdf",
+      "md5": "fa306a250a3d37fe0e7a4b3bba51c91e",
+      "type": "text"
+   }
 ]