ArcGIS Runtime SDK for iOS: AGSStretchRenderer Class Reference
ArcGIS Runtime SDK for iOS  100.13
AGSStretchRenderer Class Reference

Description

A stretch raster renderer.

Instances of this class represent a stretch renderer that can help visualize raster data using AGSRasterLayer.

A stretch renderer displays continuous raster cell values across a gradual ramp of colors. Use it to draw a single band of continuous data. The stretch renderer works well when you have a large range of values to display, such as in imagery, aerial photographs, or elevation models.

Stretching improves the appearance of the raster data by spreading its pixel values along a histogram whose minimum and maximum values are defined by the raster's bit depth. For example, an 8-bit raster dataset will be stretched along a histogram from 0 to 255.

Since
100
Inheritance diagram for AGSStretchRenderer:
AGSBaseStretchRenderer AGSRasterRenderer AGSObject

Instance Methods

(instancetype) - init
 
(instancetype) - initWithStretchParameters:gammas:estimateStatistics:colorRamp:
 

Class Methods

(instancetype) + baseStretchRenderer
 
(instancetype) + rasterRenderer
 
(instancetype) + stretchRendererWithStretchParameters:gammas:estimateStatistics:colorRamp:
 

Properties

BOOL estimateStatistics
 
NSArray< NSNumber * > * gammas
 
AGSStretchParametersstretchParameters
 

Method Documentation

◆ baseStretchRenderer

+ (instancetype) baseStretchRenderer
Deprecated:
100.9. Do not use this method, it creates an invalid and incomplete object.

◆ init

- (instancetype) init

◆ initWithStretchParameters:gammas:estimateStatistics:colorRamp:

- (instancetype) initWithStretchParameters: (AGSStretchParameters *)  stretchParameters
gammas: (NSArray< NSNumber * > *)  gammas
estimateStatistics: (BOOL)  estimateStatistics
colorRamp: (nullable AGSColorRamp *)  colorRamp 

Creates a stretch renderer.

Parameters
stretchParametersThe stretch parameters to use.
gammasAn array of values in the range 0 - 2 to apply gamma correction for each band in the raster dataset. Gamma refers to the degree of contrast between the midlevel gray values of a raster dataset. Gamma does not affect the black or white values in a raster dataset, only the middle values. By applying a gamma correction, you can control the overall brightness of a raster dataset. Additionally, gamma changes not only the brightness but also the ratios of red to green to blue. Values lower than 1 decrease the contrast in the darker areas and increase the contrast in the lighter areas. This darkens the image without saturating the dark or light areas of the image. This helps bring out details in lighter features, such as building tops. Conversely, gamma values greater than 1 increase the contrast in darker areas, such as shadows from buildings. Gamma values greater than one can also help bring out details in lower elevation areas when working with elevation data.
estimateStatisticsindicating whether statistics should be estimated for raster datasets that don't contain statistical information about their pixel values.
colorRampThe color ramp to use.
Since
100

◆ rasterRenderer

+ (instancetype) rasterRenderer

◆ stretchRendererWithStretchParameters:gammas:estimateStatistics:colorRamp:

+ (instancetype) stretchRendererWithStretchParameters: (AGSStretchParameters *)  stretchParameters
gammas: (NSArray< NSNumber * > *)  gammas
estimateStatistics: (BOOL)  estimateStatistics
colorRamp: (nullable AGSColorRamp *)  colorRamp 

Creates a stretch renderer.

Parameters
stretchParametersThe stretch parameters to use.
gammasAn array of values in the range 0 - 2 to apply gamma correction for each band in the raster dataset. Gamma refers to the degree of contrast between the midlevel gray values of a raster dataset. Gamma does not affect the black or white values in a raster dataset, only the middle values. By applying a gamma correction, you can control the overall brightness of a raster dataset. Additionally, gamma changes not only the brightness but also the ratios of red to green to blue. Values lower than 1 decrease the contrast in the darker areas and increase the contrast in the lighter areas. This darkens the image without saturating the dark or light areas of the image. This helps bring out details in lighter features, such as building tops. Conversely, gamma values greater than 1 increase the contrast in darker areas, such as shadows from buildings. Gamma values greater than one can also help bring out details in lower elevation areas when working with elevation data.
estimateStatisticsindicating whether statistics should be estimated for raster datasets that don't contain statistical information about their pixel values.
colorRampThe color ramp to use.
Returns
A new stretch renderer.
Since
100

Property Documentation

◆ estimateStatistics

- (BOOL) estimateStatistics
readnonatomicassigninherited

Indicates whether statistics should be estimated for the raster dataset. This is typically needed for datasets that do not have statistics.

Since
100

◆ gammas

- (NSArray<NSNumber*>*) gammas
readnonatomiccopyinherited

An array of values in the range 0-2 to apply gamma correction for each band in the raster dataset. Gamma refers to the degree of contrast between the midlevel gray values of a raster dataset. Gamma does not affect the black or white values in a raster dataset, only the middle values. By applying a gamma correction, you can control the overall brightness of a raster dataset. Additionally, gamma changes not only the brightness but also the ratios of red to green to blue. Values lower than 1 decrease the contrast in the darker areas and increase the contrast in the lighter areas. This darkens the image without saturating the dark or light areas of the image. This helps bring out details in lighter features, such as building tops. Conversely, gamma values greater than 1 increase the contrast in darker areas, such as shadows from buildings. Gamma values greater than one can also help bring out details in lower elevation areas when working with elevation data.

Since
100

◆ stretchParameters

- (AGSStretchParameters*) stretchParameters
readnonatomicstronginherited

The stretch parameters used for the renderer.

Since
100