Documentation / Marblecore Imaging / Methods / AdjustGamma
AdjustGamma method
Performs gamma correction on the image by a certain amount.
Syntax
Boolean AdjustGamma(nPercentage As Number, nChannel As Channel, nLeft As Number, nTop As Number, nWidth As Number, nHeight As Number)
Return value
Returns true if the function succeeded.
Parameters
Parameter | Type | Required | Description |
nPercentage | Number | Yes | The amount of the adjustment ranging from -100%...100%. A value of 0 means no change, less than 0 will make the image darker and greater than 0 will make lighten the image. |
nChannel | Channel (Enumeration) | No | Optional parameter which specifies the color channel to adjust. |
nLeft | Number | No | Optional parameter which can be used to specify a clipping rectangle. This parameter specifies the left coordinate of the rectangle. |
nTop | Number | No | Optional parameter which can be used to specify a clipping rectangle. This parameter specifies the top coordinate of the rectangle. |
nWidth | Number | No | Optional parameter which can be used to specify a clipping rectangle. This parameter specifies the width of the rectangle. |
nHeight | Number | No | Optional parameter which can be used to specify a clipping rectangle. This parameter specifies the height of the rectangle. |
Example
The example below shows the effect of this method and how to use it. You can slide the marker in the before/after picture to see the difference. If you take a look at the example code, assume there is a reference to the Marblecore Imaging object with the name 'MarblecoreImaging'. Transparent parts of the image are displayed using a checkerboard pattern.
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2 MarblecoreImaging.LoadFromFile("example-adjustgamma-before.jpg");
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5 MarblecoreImaging.AdjustGamma(25);
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8 MarblecoreImaging.SaveToFile("example-adjustgamma-after.jpg");
Category
Color adjustments
See also
AdjustBrightness |
AdjustColorBalance |
AdjustColorLevel |
AdjustContrast |
AdjustHue |
AdjustHueSaturation |
AdjustLightness |
AdjustRGB |
AdjustSaturation