Ensure clahe op uses random read, simplify validation

docs/api-operation.md

@@ -357,9 +357,9 @@ This will, in general, enhance the clarity of the image by bringing out darker d
 | Param | Type | Default | Description |
 | --- | --- | --- | --- |
 | options | <code>Object</code> |  |  |
-| options.width | <code>number</code> |  | integer width of the region in pixels. |
-| options.height | <code>number</code> |  | integer height of the region in pixels. |
-| [options.maxSlope] | <code>number</code> | <code>3</code> | maximum value for the slope of the  cumulative histogram. A value of 0 disables contrast limiting. Valid values  are integers in the range 0-100 (inclusive) |
+| options.width | <code>number</code> |  | Integral width of the search window, in pixels. |
+| options.height | <code>number</code> |  | Integral height of the search window, in pixels. |
+| [options.maxSlope] | <code>number</code> | <code>3</code> | Integral level of brightening, between 0 and 100, where 0 disables contrast limiting. |
 
 **Example**  
 ```js

lib/operation.js

@@ -512,34 +512,33 @@ function normalize (normalize) {
  *   .toBuffer();
  *
  * @param {Object} options
- * @param {number} options.width - integer width of the region in pixels.
- * @param {number} options.height - integer height of the region in pixels.
- * @param {number} [options.maxSlope=3] - maximum value for the slope of the
- *  cumulative histogram. A value of 0 disables contrast limiting. Valid values
- *  are integers in the range 0-100 (inclusive)
+ * @param {number} options.width - Integral width of the search window, in pixels.
+ * @param {number} options.height - Integral height of the search window, in pixels.
+ * @param {number} [options.maxSlope=3] - Integral level of brightening, between 0 and 100, where 0 disables contrast limiting.
  * @returns {Sharp}
  * @throws {Error} Invalid parameters
  */
 function clahe (options) {
-  if (!is.plainObject(options)) {
-    throw is.invalidParameterError('options', 'plain object', options);
-  }
-  if (!('width' in options) || !is.integer(options.width) || options.width <= 0) {
-    throw is.invalidParameterError('width', 'integer above zero', options.width);
-  } else {
-    this.options.claheWidth = options.width;
-  }
-  if (!('height' in options) || !is.integer(options.height) || options.height <= 0) {
-    throw is.invalidParameterError('height', 'integer above zero', options.height);
-  } else {
-    this.options.claheHeight = options.height;
-  }
-  if (!is.defined(options.maxSlope)) {
-    this.options.claheMaxSlope = 3;
-  } else if (!is.integer(options.maxSlope) || options.maxSlope < 0 || options.maxSlope > 100) {
-    throw is.invalidParameterError('maxSlope', 'integer 0-100', options.maxSlope);
+  if (is.plainObject(options)) {
+    if (is.integer(options.width) && options.width > 0) {
+      this.options.claheWidth = options.width;
+    } else {
+      throw is.invalidParameterError('width', 'integer greater than zero', options.width);
+    }
+    if (is.integer(options.height) && options.height > 0) {
+      this.options.claheHeight = options.height;
+    } else {
+      throw is.invalidParameterError('height', 'integer greater than zero', options.height);
+    }
+    if (is.defined(options.maxSlope)) {
+      if (is.integer(options.maxSlope) && is.inRange(options.maxSlope, 0, 100)) {
+        this.options.claheMaxSlope = options.maxSlope;
+      } else {
+        throw is.invalidParameterError('maxSlope', 'integer between 0 and 100', options.maxSlope);
+      }
+    }
   } else {
-    this.options.claheMaxSlope = options.maxSlope;
+    throw is.invalidParameterError('options', 'plain object', options);
   }
   return this;
 }

src/pipeline.cc

@@ -1659,6 +1659,7 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
       baton->rotationAngle != 0.0 ||
       baton->tileAngle != 0 ||
       baton->useExifOrientation ||
+      baton->claheWidth != 0 ||
       !baton->affineMatrix.empty()
     ) {
       baton->input->access = VIPS_ACCESS_RANDOM;