Merge pull request #7287 from ahocevar/text-line-baseline

Fix vertical stroke/fill alignment for text along lines

src/ol/render/canvas/replay.js

@@ -527,10 +527,9 @@ ol.render.canvas.Replay.prototype.replay_ = function(
         var maxAngle = /** @type {number} */ (instruction[6]);
         var measure = /** @type {function(string):number} */ (instruction[7]);
         var offsetY = /** @type {number} */ (instruction[8]);
-        var strokeWidth = /** @type {number} */ (instruction[9]);
-        var text = /** @type {string} */ (instruction[10]);
-        var align = /** @type {number} */ (instruction[11]);
-        var textScale = /** @type {number} */ (instruction[12]);
+        var text = /** @type {string} */ (instruction[9]);
+        var align = /** @type {number} */ (instruction[10]);
+        var textScale = /** @type {number} */ (instruction[11]);
 
         var pathLength = ol.geom.flat.length.lineString(pixelCoordinates, begin, end, 2);
         var textLength = measure(text);
@@ -540,11 +539,12 @@ ol.render.canvas.Replay.prototype.replay_ = function(
               pixelCoordinates, begin, end, 2, text, measure, startM, maxAngle, this.chars_);
           var numChars = text.length;
           if (chars) {
+            var fillHeight = images[images.length - 1].height;
             for (var c = 0, cc = images.length; c < cc; ++c) {
               var char = chars[c % numChars]; // x, y, rotation
               var label = images[c];
               anchorX = label.width / 2;
-              anchorY = baseline * label.height + 2 * (0.5 - baseline) * strokeWidth - offsetY;
+              anchorY = baseline * label.height + (0.5 - baseline) * (label.height - fillHeight) - offsetY;
               this.replayImage_(context, char[0], char[1], label, anchorX, anchorY,
                   label.height, 1, 0, 0, char[2], textScale, false, label.width);
             }

src/ol/render/canvas/textreplay.js

@@ -383,7 +383,6 @@ ol.render.canvas.TextReplay.prototype.drawChars_ = function(begin, end) {
   var stroke = !!strokeState;
   var textState = this.textState_;
   var baseline = ol.render.replay.TEXT_ALIGN[textState.textBaseline];
-  var strokeWidth = stroke && strokeState.lineWidth ? strokeState.lineWidth * pixelRatio : 0;
 
   var labels = [];
   var text = this.text_;
@@ -409,13 +408,13 @@ ol.render.canvas.TextReplay.prototype.drawChars_ = function(begin, end) {
     begin, end, labels, baseline,
     textState.exceedLength, textState.maxAngle,
     ol.render.canvas.TextReplay.getTextWidth.bind(widths, context, pixelRatio),
-    offsetY, strokeWidth, this.text_, align, this.textScale_
+    offsetY, this.text_, align, this.textScale_
   ]);
   this.hitDetectionInstructions.push([ol.render.canvas.Instruction.DRAW_CHARS,
     begin, end, labels, baseline,
     textState.exceedLength, textState.maxAngle,
     ol.render.canvas.TextReplay.getTextWidth.bind(widths, context, 1),
-    offsetY, strokeWidth, this.text_, align, this.textScale_ / pixelRatio
+    offsetY, this.text_, align, this.textScale_ / pixelRatio
   ]);
 };
 

test/rendering/ol/style/text.test.js

@@ -99,7 +99,7 @@ describe('ol.rendering.style.Text', function() {
     var uglyPath = [163, 22, 159, 30, 150, 30, 143, 24, 151, 17];
     var polygon = [151, 17, 163, 22, 159, 30, 150, 30, 143, 24, 151, 17];
 
-    function createLineString(coords, textAlign, maxAngle) {
+    function createLineString(coords, textAlign, maxAngle, strokeColor, strokeWidth) {
       var geom = new ol.geom.LineString();
       geom.setFlatCoordinates('XY', coords);
       var style = new ol.style.Style({
@@ -113,7 +113,8 @@ describe('ol.rendering.style.Text', function() {
           maxAngle: maxAngle,
           placement: 'line',
           stroke: new ol.style.Stroke({
-            color: 'white'
+            color: strokeColor || 'white',
+            width: strokeWidth
           })
         })
       });
@@ -282,13 +283,20 @@ describe('ol.rendering.style.Text', function() {
       it('renders text along a linestring', function(done) {
         createMap('canvas');
         createLineString(nicePath);
-        expectResemble(map, 'rendering/ol/style/expected/text-linestring-nice.png', 2.5, done);
+        expectResemble(map, 'rendering/ol/style/expected/text-linestring-nice.png', 2.8, done);
+      });
+
+      it('aligns text along a linestring correctly with `textBaseline` option', function(done) {
+        createMap('canvas');
+        createLineString(nicePath, undefined, undefined, 'cyan', 3);
+        map.getView().setResolution(0.25);
+        expectResemble(map, 'rendering/ol/style/expected/text-linestring-nice-baseline.png', 6.2, done);
       });
 
       it('renders text along a linestring with `textAlign: \'left\'`', function(done) {
         createMap('canvas');
         createLineString(nicePath, 'left');
-        expectResemble(map, 'rendering/ol/style/expected/text-linestring-left-nice.png', 2.5, done);
+        expectResemble(map, 'rendering/ol/style/expected/text-linestring-left-nice.png', 2.8, done);
       });
 
       it('renders text along a rotated linestring', function(done) {