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Class: StretchFilter
[ AMD Module Require | Legacy Module Require ]
require(["esri/layers/pixelFilters/StretchFilter"], function(StretchFilter) { /* code goes here */ });
Description
(Added at v3.18)
A stretch filter used to work with client -side pixel data to enhance raster/image appearances. This can be used in conjunction with RasterLayer or WCSLayer.Samples
Search for samples that use this class.Constructors
| Name | Summary |
|---|---|
| new StretchFilter(options?) | Creates an instance of a StretchFilter. |
Properties
| Name | Type | Summary |
|---|---|---|
| dra | Boolean | Indicates whether to perform dynamic range adjustment using the current pixel data. |
| gamma | Number[] | An array of gamma values, for example [0.8, 0.8, 0.8]. |
| max | Number | The maximum value of stretched pixels. |
| maxPercent | Number | Percent of pixels clipped on the right histogram tail, for example 0.25. |
| min | Number | The minimum value of stretched pixels. |
| minPercent | Number | Percent of pixels clipped on the left histogram tail, for example 1.5. |
| numberOfStandardDeviations | Number | The number of standard deviations for StandardDeviation stretch, for example 2.5. |
| outputPixelType | String | The output pixel type. |
| statistics | Array[] | An array of arrays containing custom statistics objects. |
| stretchType | Number | Number indicating the various stretch types. |
| useGamma | Boolean | Indicates whether to perform non-linear gamma stretch. |
Methods
| Name | Return type | Summary |
|---|---|---|
| filter(pixelData) | None | It takes a pixelData object as input and processes it. |
Constructor Details
Creates an instance of a StretchFilter.
Parameters:
< |
Optional | Optional parameters. See options list below. |
options properties: < |
Optional | Indicates whether to perform dynamic range adjustment using the current pixel data. |
< |
Optional | An array of gamma values, for example [0.8, 0.8, 0.8]. |
< |
Optional | The maximum value of stretched pixels. Default value is 255. |
< |
Optional | Percent of pixels clipped on the right histogram tail, for example 0.25. |
< |
Optional | The minimum value of stretched pixels. Default value is 0
|
< |
Optional | Percent of pixels clipped on the left histogram tail, for example 1.5. |
< |
Optional | The number of standard deviations for StandardDeviation stretch, for example 2.5. |
< |
Optional | The output pixel type. Set this to U8 to avoid extra stretch by the layer. |
< |
Optional | An array of arrays containing custom statistics objects. Each element represents a band statistic, i.e. [min, max, mean, standardDeviation]. |
< |
Optional | See the constants table for a list of possible stretchType values. |
< |
Optional | Indicates whether to perform non-linear gamma stretch. |
Sample:
var stretch = new StretchFilter({
"stretchType": 6,
"min": 0,
"max": 255,
"dra": true,
"minPercent": 0.2,
"maxPercent": 0.2,
"useGamma": false,
});
var rasterLayer = new RasterLayer{
url: "url",
pixelFilter:stretch.filter
};
Property Details
<Boolean
BooleanIndicates whether to perform dynamic range adjustment using the current pixel data.
<Number[]
Number[]An array of gamma values, for example
[0.8, 0.8, 0.8].<Number
NumberPercent of pixels clipped on the right histogram tail, for example
0.25.<Number
NumberPercent of pixels clipped on the left histogram tail, for example
1.5.<Number
NumberThe number of standard deviations for StandardDeviation stretch, for example
2.5.<String
StringThe output pixel type. Set this to
U8 to avoid extra stretch by the layer.<Array[]
Array[]An array of arrays containing custom statistics objects. Each element represents a band statistic, i.e.
[min, max, mean, standardDeviation].<Number
NumberNumber indicating the various stretch types. These include:
- 0 - No stretch filter
- 3 - StandardDeviation
- 4 - Histogram Equalization
- 5 - MinMax
- 6 - Percent Clip
<Boolean
BooleanIndicates whether to perform non-linear gamma stretch.
Method Details
It takes a
pixelData object as input and processes it. The pixelData object contains a pixelBlock property that gives you access to all of the pixels in the raster.
Inside the pixelFilter, you may loop through pixels through the pixelBlock property of the pixelData object and process them.
Parameters:
< |
Required | The pixelData object used as filter input. The pixelData object contains a pixelBlock property that gives you access to all of the pixels in the raster.
Inside the pixelFilter, you may loop through pixels through the pixelBlock property of the pixelData object and process them. |