Merge pull request #14703 from calixteman/14627

[text selection] Add the whitespaces present in the pdf in the text chunk

src/core/evaluator.js

@@ -2187,17 +2187,62 @@ class PartialEvaluator {
       spaceInFlowMax: 0,
       trackingSpaceMin: Infinity,
       negativeSpaceMax: -Infinity,
+      notASpace: -Infinity,
       transform: null,
       fontName: null,
       hasEOL: false,
     };
 
+    // Use a circular buffer (length === 2) to save the last chars in the
+    // text stream.
+    // This implementation of the circular buffer is using a fixed array
+    // and the position of the next element:
+    // function addElement(x) {
+    //   buffer[pos] = x;
+    //   pos = (pos + 1) % buffer.length;
+    // }
+    // It's a way faster than:
+    // function addElement(x) {
+    //   buffer.push(x);
+    //   buffer.shift();
+    // }
+    //
+    // It's useful to know when we need to add a whitespace in the
+    // text chunk.
+    const twoLastChars = [" ", " "];
+    let twoLastCharsPos = 0;
+
+    /**
+     * Save the last char.
+     * @param {string} char
+     * @returns {boolean} true when the two last chars before adding the new one
+     * are a non-whitespace followed by a whitespace.
+     */
+    function saveLastChar(char) {
+      const nextPos = (twoLastCharsPos + 1) % 2;
+      const ret =
+        twoLastChars[twoLastCharsPos] !== " " && twoLastChars[nextPos] === " ";
+      twoLastChars[twoLastCharsPos] = char;
+      twoLastCharsPos = nextPos;
+
+      return ret;
+    }
+
+    function resetLastChars() {
+      twoLastChars[0] = twoLastChars[1] = " ";
+      twoLastCharsPos = 0;
+    }
+
     // Used in addFakeSpaces.
 
     // A white <= fontSize * TRACKING_SPACE_FACTOR is a tracking space
     // so it doesn't count as a space.
     const TRACKING_SPACE_FACTOR = 0.1;
 
+    // When a white <= fontSize * NOT_A_SPACE_FACTOR, there is no space
+    // even if one is present in the text stream.
+    const NOT_A_SPACE_FACTOR = 0.03;
+
     // A negative white < fontSize * NEGATIVE_SPACE_FACTOR induces
     // a break (a new chunk of text is created).
     // It doesn't change anything when the text is copied but
@@ -2299,6 +2344,7 @@ class PartialEvaluator {
 
       textContentItem.trackingSpaceMin =
         textState.fontSize * TRACKING_SPACE_FACTOR;
+      textContentItem.notASpace = textState.fontSize * NOT_A_SPACE_FACTOR;
       textContentItem.negativeSpaceMax =
         textState.fontSize * NEGATIVE_SPACE_FACTOR;
       textContentItem.spaceInFlowMin =
@@ -2483,6 +2529,7 @@ class PartialEvaluator {
             return true;
           }
 
+          resetLastChars();
           flushTextContentItem();
           return true;
         }
@@ -2491,6 +2538,13 @@ class PartialEvaluator {
           appendEOL();
           return true;
         }
+
+        if (advanceY <= textOrientation * textContentItem.notASpace) {
+          // The real spacing between 2 consecutive chars is thin enough to be
+          // considered a non-space.
+          resetLastChars();
+        }
+
         if (advanceY <= textOrientation * textContentItem.trackingSpaceMin) {
           textContentItem.height += advanceY;
         } else if (
@@ -2501,6 +2555,7 @@ class PartialEvaluator {
           )
         ) {
           if (textContentItem.str.length === 0) {
+            resetLastChars();
             textContent.items.push({
               str: " ",
               dir: "ltr",
@@ -2532,6 +2587,10 @@ class PartialEvaluator {
           appendEOL();
           return true;
         }
+
+        // We're moving back so in case the last char was a whitespace
+        // we cancel it: it doesn't make sense to insert it.
+        resetLastChars();
         flushTextContentItem();
         return true;
       }
@@ -2541,12 +2600,19 @@ class PartialEvaluator {
         return true;
       }
 
+      if (advanceX <= textOrientation * textContentItem.notASpace) {
+        // The real spacing between 2 consecutive chars is thin enough to be
+        // considered a non-space.
+        resetLastChars();
+      }
+
       if (advanceX <= textOrientation * textContentItem.trackingSpaceMin) {
         textContentItem.width += advanceX;
       } else if (
         !addFakeSpaces(advanceX, textContentItem.prevTransform, textOrientation)
       ) {
         if (textContentItem.str.length === 0) {
+          resetLastChars();
           textContent.items.push({
             str: " ",
             dir: "ltr",
@@ -2600,14 +2666,7 @@ class PartialEvaluator {
         }
         let scaledDim = glyphWidth * scale;
 
-        if (
+        if (glyph.isWhitespace) {
-          glyph.isWhitespace &&
-          (i === 0 ||
-            i + 1 === ii ||
-            glyphs[i - 1].isWhitespace ||
-            glyphs[i + 1].isWhitespace ||
-            extraSpacing)
-        ) {
           // Don't push a " " in the textContentItem
           // (except when it's between two non-spaces chars),
           // it will be done (if required) in next call to
@@ -2623,6 +2682,7 @@ class PartialEvaluator {
             charSpacing += -scaledDim + textState.wordSpacing;
             textState.translateTextMatrix(0, -charSpacing);
           }
+          saveLastChar(" ");
           continue;
         }
 
@@ -2653,17 +2713,18 @@ class PartialEvaluator {
           textChunk.prevTransform = getCurrentTextTransform();
         }
 
-        if (glyph.isWhitespace) {
+        let glyphUnicode = glyph.unicode;
+        glyphUnicode = NormalizedUnicodes[glyphUnicode] || glyphUnicode;
+        glyphUnicode = reverseIfRtl(glyphUnicode);
+        if (saveLastChar(glyphUnicode)) {
+          // The two last chars are a non-whitespace followed by a whitespace
+          // and then this non-whitespace, so we insert a whitespace here.
           // Replaces all whitespaces with standard spaces (0x20), to avoid
           // alignment issues between the textLayer and the canvas if the text
           // contains e.g. tabs (fixes issue6612.pdf).
           textChunk.str.push(" ");
-        } else {
-          let glyphUnicode = glyph.unicode;
-          glyphUnicode = NormalizedUnicodes[glyphUnicode] || glyphUnicode;
-          glyphUnicode = reverseIfRtl(glyphUnicode);
-          textChunk.str.push(glyphUnicode);
         }
+        textChunk.str.push(glyphUnicode);
 
         if (charSpacing) {
           if (!font.vertical) {
@@ -2679,6 +2740,7 @@ class PartialEvaluator {
     }
 
     function appendEOL() {
+      resetLastChars();
       if (textContentItem.initialized) {
         textContentItem.hasEOL = true;
         flushTextContentItem();
@@ -2701,6 +2763,7 @@ class PartialEvaluator {
         width <= textOrientation * textContentItem.spaceInFlowMax
       ) {
         if (textContentItem.initialized) {
+          resetLastChars();
           textContentItem.str.push(" ");
         }
         return false;
@@ -2715,6 +2778,7 @@ class PartialEvaluator {
       }
 
       flushTextContentItem();
+      resetLastChars();
       textContent.items.push({
         str: " ",
         // TODO: check if using the orientation from last chunk is

test/pdfs/.gitignore

@@ -515,3 +515,4 @@
 !issue14497.pdf
 !issue14502.pdf
 !issue13211.pdf
+!issue14627.pdf

test/test_manifest.json

@@ -6329,5 +6329,11 @@
       "md5": "d193853e8a123dc50eeea593a4150b60",
       "rounds": 1,
       "type": "eq"
+   },
+   {  "id": "issue14627",
+      "file": "pdfs/issue14627.pdf",
+      "md5": "5d1bfcc3b3130bfa7e33e43990e2213a",
+      "rounds": 1,
+      "type": "text"
    }
 ]

test/unit/api_spec.js

@@ -1999,7 +1999,7 @@ describe("api", function () {
       const data = await Promise.all([defaultPromise, parametersPromise]);
 
       expect(!!data[0].items).toEqual(true);
-      expect(data[0].items.length).toEqual(11);
+      expect(data[0].items.length).toEqual(15);
       expect(!!data[0].styles).toEqual(true);
 
       const page1 = mergeText(data[0].items);

test/unit/pdf_find_controller_spec.js

@@ -579,14 +579,14 @@ describe("pdf_find_controller", function () {
       },
       pageMatches: [
         [
-          299, 337, 414, 476, 623, 797, 978, 984, 1010, 1058, 1079, 1144, 1152,
+          302, 340, 418, 481, 628, 802, 983, 989, 1015, 1063, 1084, 1149, 1157,
-          1274, 1343, 1391, 1399, 1421, 1497, 1521, 1527, 1684, 1774, 1786,
+          1278, 1346, 1394, 1402, 1424, 1500, 1524, 1530, 1686, 1776, 1788,
-          1857, 1879, 1909, 1946, 2064, 2074, 2161, 2178, 2213, 2227, 2272,
+          1859, 1881, 1911, 1948, 2066, 2076, 2163, 2180, 2215, 2229, 2274,
-          2322, 2359, 2401, 2412, 2423, 2462, 2532, 2538, 2553, 2562, 2576,
+          2324, 2360, 2402, 2413, 2424, 2463, 2532, 2538, 2553, 2562, 2576,
-          2602, 2613, 2638, 2668, 2792, 2805, 2836, 2848, 2859, 2896, 2902,
+          2602, 2613, 2638, 2668, 2792, 2805, 2836, 2847, 2858, 2895, 2901,
-          2916, 2940, 2960, 3091, 3239, 3249, 3339, 3387, 3394, 3468, 3477,
+          2915, 2939, 2959, 3089, 3236, 3246, 3336, 3384, 3391, 3465, 3474,
-          3485, 3502, 3690, 3696, 3711, 3758, 3789, 3865, 3977, 4052, 4058,
+          3482, 3499, 3687, 3693, 3708, 3755, 3786, 3862, 3974, 4049, 4055,
-          4071,
+          4068,
         ],
       ],
       pageMatchesLength: [