Deprecate background, add op-specific prop to resize/extend/flatten #1392

lib/constructor.js

@@ -105,6 +105,7 @@ const Sharp = function (input, options) {
     height: -1,
     canvas: 'crop',
     position: 0,
+    resizeBackground: [0, 0, 0, 255],
     useExifOrientation: false,
     angle: 0,
     rotationAngle: 0,
@@ -116,14 +117,15 @@ const Sharp = function (input, options) {
     extendBottom: 0,
     extendLeft: 0,
     extendRight: 0,
+    extendBackground: [0, 0, 0, 255],
     withoutEnlargement: false,
     kernel: 'lanczos3',
     fastShrinkOnLoad: true,
     // operations
-    background: [0, 0, 0, 255],
     tintA: 128,
     tintB: 128,
     flatten: false,
+    flattenBackground: [0, 0, 0],
     negate: false,
     medianSize: 0,
     blurSigma: 0,