Merge pull request #5354 from almarklein/interp

Implement fast zsmooth option for image trace

Author: archmoj

src/traces/image/attributes.js

@@ -51,6 +51,17 @@ module.exports = extendFlat({
             'otherwise it defaults to `rgb`.'
         ].join(' ')
     },
+    zsmooth: {
+        valType: 'enumerated',
+        values: ['fast', false],
+        dflt: false,
+        role: 'info',
+        editType: 'plot',
+        description: [
+            'Picks a smoothing algorithm used to smooth `z` data.',
+            'This only applies for image traces that use the `source` attribute.'
+        ].join(' ')
+    },
     zmin: {
         valType: 'info_array',
         items: [

src/traces/image/constants.js

@@ -55,5 +55,18 @@ module.exports = {
             },
             suffix: ['°', '%', '%', '']
         }
-    }
+    },
+    // For pixelated image rendering
+    // http://phrogz.net/tmp/canvas_image_zoom.html
+    // https://developer.mozilla.org/en-US/docs/Web/CSS/image-rendering
+    pixelatedStyle: [
+        'image-rendering: optimizeSpeed',
+        'image-rendering: -moz-crisp-edges',
+        'image-rendering: -o-crisp-edges',
+        'image-rendering: -webkit-optimize-contrast',
+        'image-rendering: optimize-contrast',
+        'image-rendering: crisp-edges',
+        'image-rendering: pixelated',
+        ''
+    ].join('; ')
 };

src/traces/image/defaults.js

@@ -47,6 +47,7 @@ module.exports = function supplyDefaults(traceIn, traceOut) {
         traceOut.zmax = cm.zmaxDflt;
     }
 
+    coerce('zsmooth');
     coerce('text');
     coerce('hovertext');
     coerce('hovertemplate');

src/traces/image/plot.js

@@ -136,10 +136,8 @@ module.exports = function plot(gd, plotinfo, cdimage, imageLayer) {
 
         image3.exit().remove();
 
-        // Pixelated image rendering
-        // http://phrogz.net/tmp/canvas_image_zoom.html
-        // https://developer.mozilla.org/en-US/docs/Web/CSS/image-rendering
-        var style = 'image-rendering: optimizeSpeed; image-rendering: -moz-crisp-edges; image-rendering: -o-crisp-edges; image-rendering: -webkit-optimize-contrast; image-rendering: optimize-contrast; image-rendering: crisp-edges; image-rendering: pixelated;';
+        var style = (trace.zsmooth === false) ? constants.pixelatedStyle : '';
+
         if(fastImage) {
             var xRange = Lib.simpleMap(xa.range, xa.r2l);
             var yRange = Lib.simpleMap(ya.range, ya.r2l);