Custom Image Filter Engine (in VB6)

The ability to create custom filters is a mainstay of any quality graphics application.  A robust matrix-based filter engine can generate hundreds of unique effects by simply adjusting the matrices that get passed into the engine.

In this project, I’ve provided a 5×5 custom filter engine with support for scaling/weighting and biasing/offsetting.  This is identical to the custom filter engine provided by Photoshop, and mine is even slightly faster (at least for the screen-sized images I’ve been testing).

Besides being fast, the engine is also smart.  It is clever enough to estimate edge pixels correctly – even for scaled/weighted filters – and it will automatically validate all input values to make sure they’re appropriate.

Finally, I’ve included 7 sample filters for you to play with, including blur, sharpen, emboss, engrave, grease, unfocus, and vibrate.

Download Custom Filter Engine Code (91 kb)

Below, you can see how each filter looks on a promotional image from Castle, an excellent new NYPD dramedy on ABC.

Original:

Blur:

Sharpen:

Emboss:

Engrave:

Grease:

Unfocus:

Vibrate:

Related articles:

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• Sepia / “Antique” Image Effect (in VB6)
• Real-time Image Curves (using cubic splines) in VB6