renamed ColorStretch filter to Enhance. cleaned up the code a bit. updated tests. changed function signature back to just image data

src/filters/ColorStretch.js

@@ -1,101 +0,0 @@
-(function () {
-  function remap(fromValue, fromMin, fromMax, toMin, toMax) {
-
-    // Make sure min is less than max (covered outside)
-    /*
-    var swap;
-    if (fromMin > fromMax) {
-      swap = fromMax;
-      fromMin = fromMax;
-      fromMin = swap;
-    }
-    if (toMin > toMax) {
-      swap = toMax;
-      toMin = toMax;
-      toMin = swap;
-    }
-    */
-
-    // Compute the range of the data
-    var fromRange = fromMax - fromMin;
-    var toRange = toMax - toMin;
-
-    // If either range is 0, then the value can only be mapped to 1 value
-    if (fromRange === 0) {
-      return toMin + toRange / 2;
-    }
-    if (toRange === 0) {
-      return toMin;
-    }
-
-    // (1) untranslate, (2) unscale, (3) rescale, (4) retranslate
-    var toValue = (fromValue - fromMin) / fromRange;
-    toValue = (toRange * toValue) + toMin;
-
-    return toValue;
-  }
-
-
-  /**
-   * ColorStretch Filter. Adjusts the colors so that they span the widest
-   *  possible range (ie 0-255). Performs w*h pixel reads and w*h pixel
-   *  writes.
-   * @function
-   * @author ippo615
-   * @memberof Kinetic.Filters
-   * @param {ImageData} src, the source image data (what will be transformed)
-   * @param {ImageData} dst, the destination image data (where it will be saved)
-   * @param {Object} opt, There are no options for this filter
-   */
-
-  var ColorStretch = function (src, dst, opt) {
-    var srcPixels = src.data,
-      dstPixels = dst.data,
-      nPixels = srcPixels.length,
-      i;
-
-    // 1st Pass - find the min and max for each channel:
-    var rMin = srcPixels[0], rMax = rMin, r,
-      gMin = srcPixels[1], gMax = gMin, g,
-      bMin = srcPixels[3], bMax = bMin, b,
-      aMin = srcPixels[4], aMax = aMin, a;
-    for (i = 0; i < nPixels; i += 4) {
-      r = srcPixels[i + 0];
-      if (r < rMin) { rMin = r; } else
-      if (r > rMax) { rMax = r; }
-      g = srcPixels[i + 1];
-      if (g < gMin) { gMin = g; } else
-      if (g > gMax) { gMax = g; }
-      b = srcPixels[i + 2];
-      if (b < bMin) { bMin = b; } else
-      if (b > bMax) { bMax = b; }
-      a = srcPixels[i + 3];
-      if (a < aMin) { aMin = a; } else
-      if (a > aMax) { aMax = a; }
-    }
-
-    // If there is only 1 level - don't remap
-    if( rMax === rMin ){ rMax = 255; rMin = 0; }
-    if( gMax === gMin ){ gMax = 255; gMin = 0; }
-    if( bMax === bMin ){ bMax = 255; bMin = 0; }
-    if( aMax === aMin ){ aMax = 255; aMin = 0; }
-
-    // Pass 2 - remap everything to fill the full range
-    for (i = 0; i < nPixels; i += 1) {
-      dstPixels[i + 0] = remap(srcPixels[i + 0], rMin, rMax, 0, 255);
-      dstPixels[i + 1] = remap(srcPixels[i + 1], gMin, gMax, 0, 255);
-      dstPixels[i + 2] = remap(srcPixels[i + 2], bMin, bMax, 0, 255);
-      dstPixels[i + 3] = remap(srcPixels[i + 3], aMin, aMax, 0, 255);
-    }
-
-  };
-
-  Kinetic.Filters.ColorStretch = function(src,dst,opt){
-    if( this === Kinetic.Filters ){
-      ColorStretch(src, dst||src, opt );
-    }else{
-      ColorStretch.call(this, src, dst||src, opt);
-    }
-  };
-
-})();

src/filters/Enhance.js

@@ -0,0 +1,72 @@
+(function () {
+  function remap(fromValue, fromMin, fromMax, toMin, toMax) {
+    // Compute the range of the data
+    var fromRange = fromMax - fromMin,
+        toRange = toMax - toMin,
+        toValue;
+
+    // If either range is 0, then the value can only be mapped to 1 value
+    if (fromRange === 0) {
+      return toMin + toRange / 2;
+    }
+    if (toRange === 0) {
+      return toMin;
+    }
+
+    // (1) untranslate, (2) unscale, (3) rescale, (4) retranslate
+    toValue = (fromValue - fromMin) / fromRange;
+    toValue = (toRange * toValue) + toMin;
+
+    return toValue;
+  }
+
+
+  /**
+   * Enhance Filter. Adjusts the colors so that they span the widest
+   *  possible range (ie 0-255). Performs w*h pixel reads and w*h pixel
+   *  writes.
+   * @function
+   * @memberof Kinetic.Filters
+   * @param {Object} imageData
+   * @author ippo615
+   */
+  Kinetic.Filters.Enhance = function (imageData) {
+    var data = imageData.data,
+        nPixels = data.length,
+        rMin = data[0], rMax = rMin, r,
+        gMin = data[1], gMax = gMin, g,
+        bMin = data[3], bMax = bMin, b,
+        aMin = data[4], aMax = aMin, a,
+        i;
+
+    // 1st Pass - find the min and max for each channel:
+    for (i = 0; i < nPixels; i += 4) {
+      r = data[i + 0];
+      if (r < rMin) { rMin = r; } else
+      if (r > rMax) { rMax = r; }
+      g = data[i + 1];
+      if (g < gMin) { gMin = g; } else
+      if (g > gMax) { gMax = g; }
+      b = data[i + 2];
+      if (b < bMin) { bMin = b; } else
+      if (b > bMax) { bMax = b; }
+      a = data[i + 3];
+      if (a < aMin) { aMin = a; } else
+      if (a > aMax) { aMax = a; }
+    }
+
+    // If there is only 1 level - don't remap
+    if( rMax === rMin ){ rMax = 255; rMin = 0; }
+    if( gMax === gMin ){ gMax = 255; gMin = 0; }
+    if( bMax === bMin ){ bMax = 255; bMin = 0; }
+    if( aMax === aMin ){ aMax = 255; aMin = 0; }
+
+    // Pass 2 - remap everything to fill the full range
+    for (i = 0; i < nPixels; i += 1) {
+      data[i + 0] = remap(data[i + 0], rMin, rMax, 0, 255);
+      data[i + 1] = remap(data[i + 1], gMin, gMax, 0, 255);
+      data[i + 2] = remap(data[i + 2], bMin, bMax, 0, 255);
+      data[i + 3] = remap(data[i + 3], aMin, aMax, 0, 255);
+    }
+  };
+})();