Overloading fill color (polygon or text) with CanvasPattern and CanvasGradient.

2016-01-06 09:57:40 -08:00
parent aa508acde4
commit 7f02b63ccc
8 changed files with 77 additions and 21 deletions
@@ -0,0 +1,41 @@
+goog.provide('ol.ColorLike');
+goog.provide('ol.colorlike');
+
+goog.require('ol.color');
+
+
+/**
+ * A type accepted by CanvasRenderingContext2D.fillStyle.
+ * Represents a color, pattern, or gradient.
+ *
+ * @typedef {string|CanvasPattern|CanvasGradient}
+ * @api
+ */
+ol.ColorLike;
+
+
+/**
+ * @param {ol.Color|ol.ColorLike} color Color.
+ * @return {ol.ColorLike} The color as an ol.ColorLike
+ * @api
+ */
+ol.colorlike.asColorLike = function(color) {
+  if (ol.colorlike.isColorLike(color)) {
+    return /** @type {string|CanvasPattern|CanvasGradient} */ (color);
+  } else {
+    return ol.color.asString(/** @type {ol.Color} */ (color));
+  }
+};
+
+
+/**
+ * @param {?} color The value that is potentially an ol.ColorLike
+ * @return {boolean} Whether the color is an ol.ColorLike
+ */
+ol.colorlike.isColorLike = function(color) {
+  return (
+      goog.isString(color) ||
+      color instanceof CanvasPattern ||
+      color instanceof CanvasGradient
+  );
+};