Extracting Windows from an Image

When we are working with very large bitmaps generated by rasterizers we often wish to discuss the behavior on a particular structure. In such as case it is helpful to be able to extract from the large and unwieldy bitmap, a small window of pixels surrounding the region under consideration.

Multiple Layers?

If you have multiple layers loaded only the "active" layer is extracted. Future versions of this software may enable extraction of multiple layers to a single file.

The Extraction Dialog

The extract function is launched from the menu File | Extract.

extraction dialog

Methods of Specifying a Window

There are four different ways of extracting a window from the input image:

Select Window

Shifts focus to the display where the user selects the window using the mouse.

Current Window

Uses the extents of the display window

Lower Left and Upper Right

User enters the lower left and upper right corners of the window into the fields provided.

Center, Width and Height

User enters the window center and its width and height.

File Formats

Available output formats are:


Microsoft BMP format. No compression options. Supports greyscale output.


Adobe TIFF format. Packbits compression for monochrome output. Supporst greyscale output.


A non-standard method of supporting TIFF files > 4 GB. Supports packbits compression and greyscale.


pure raster data with no header. Monochrome only. No greyscale option.


Custom RAW file developed for LG, Korea.

Grayscale Conversion

The extracted file can be converted to greyscale. See the Greyscale page for details.