perf: remove unnecessary context.save()& context.restore()

smoothie.js

@@ -844,10 +844,6 @@
 
     context.font = chartOptions.labels.fontSize + 'px ' + chartOptions.labels.fontFamily;
 
-    // Save the state of the canvas context, any transformations applied in this method
-    // will get removed from the stack at the end of this method when .restore() is called.
-    context.save();
-
     // Move the origin.
     context.translate(dimensions.left, dimensions.top);
 
@@ -859,14 +855,11 @@
     context.clip();
 
     // Clear the working area.
-    context.save();
     context.fillStyle = chartOptions.grid.fillStyle;
     context.clearRect(0, 0, dimensions.width, dimensions.height);
     context.fillRect(0, 0, dimensions.width, dimensions.height);
-    context.restore();
 
     // Grid lines...
-    context.save();
     context.lineWidth = chartOptions.grid.lineWidth;
     context.strokeStyle = chartOptions.grid.strokeStyle;
     // Vertical (time) dividers.
@@ -904,7 +897,6 @@
       context.strokeRect(0, 0, dimensions.width, dimensions.height);
       context.closePath();
     }
-    context.restore();
 
     // Draw any horizontal lines...
     if (chartOptions.horizontalLines && chartOptions.horizontalLines.length) {
@@ -931,7 +923,6 @@
       if (dataSet.length <= 1 || timeSeries.disabled) {
           continue;
       }
-      context.save();
 
       var seriesOptions = this.seriesSet[d].options;
 
@@ -1007,8 +998,6 @@
         context.stroke();
       }
       context.closePath();
-
-      context.restore();
     }
 
     if (chartOptions.tooltip && this.mouseX >= 0) {
@@ -1106,8 +1095,6 @@
       context.fillStyle = chartOptions.title.fillStyle;
       context.fillText(chartOptions.title.text, titleXPos, titleYPos);
     }
-
-    context.restore(); // See .save() above.
   };
 
   // Sample timestamp formatting function