ArcGIS Runtime SDK for iOS: AGSBaseStretchRenderer Class Reference
ArcGIS Runtime SDK for iOS  100.15
AGSBaseStretchRenderer Class Reference


An abstract base stretch renderer object which is derived from a raster renderer object.

A base class for stretch renderers that can help visualize raster data using AGSRasterLayer.

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.

See also
Inheritance diagram for AGSBaseStretchRenderer:
AGSRasterRenderer AGSObject AGSRGBRenderer AGSStretchRenderer

Instance Methods

(instancetype) - init

Class Methods

(instancetype) + baseStretchRenderer
(instancetype) + rasterRenderer


BOOL estimateStatistics
NSArray< NSNumber * > * gammas

Method Documentation

◆ baseStretchRenderer

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

◆ init

- (instancetype) init

◆ rasterRenderer

+ (instancetype) rasterRenderer

Property Documentation

◆ estimateStatistics

- (BOOL) estimateStatistics

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


◆ gammas

- (NSArray<NSNumber*>*) gammas

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.


◆ stretchParameters

- (AGSStretchParameters*) stretchParameters

The stretch parameters used for the renderer.