Overview

The ImageEdit library provides photographic image manipulation functions for Basic4PPC applications. This library will run on both the desktop and the device but requires .NET 2.0 or later

Within the Image Edit library you will find the ImageEdit object.

The library accepts 24 (3 x 8) bit colour bitmaps and saves them internally as linearised 3 x 15 bit values using a default gamma of 2.2. A different input gamma may be specified before loading a bitmap if required. Linearising is needed to avoid colour shifts during processing and the additional resolution helps avoid information loss and consequent colour banding and blocking that might occur if 8 bit values were used.

Various image processing functions may be applied to this internal version of the image which may then be returned as a gamma corrected 24 bit image. The default output gamma is 2.2 but other values may be specified. The image may also be saved to a file in various formats.

Instead of using built-in functions such as Soften or Sharpen the libary accepts 3 x 3 convolution filter parameters enabling the various processing functions to be specified by the implementer. Google is your friend to find out more, start with a search on "3 x 3 image filter matrix".

Input and ouput gamma aside most of the image manipulations operations are linear functions. However non-linear operations can be a approximated by the Curve method. This takes an Array(256) of percentage values and allows individual bands of colour values to have different percentage adjustments aplied to them. This allows such things as lifting shadow details and suppressing highlights.