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8BIT COLOR PALETTE CONVERTER CODE

8BIT COLOR PALETTE CONVERTER CODE

It is one of the principles for time critical code development – do not allocate memory on demand, but perform allocation before.

Decrease the number of memory allocations inside the loop.

You can check the cost of such an invocation with a profiler - for sure, it is more expensive than reading it only one time to some temp variable before the loop. There are two invocations of Bitmap width and height properties for each pixel (its mean is 2M invocations). For example, see the double loop of ConvertTo8bppFormat.

Decrease the number of property and method invocations of.

Decrease the number of iterations, its mean, read all source information at once and copy all destination information at once.

So I'll perform the following steps to improve performance: During iteration, the code reads pixel's information from the source bitmap, then matches some known color (256 iterations in the worst case) and then copies it to the destination. The core of this method is a double loop (width X height), so for big bitmaps (1024x768 and bigger) there are millions and more iterations.

So let's see the reasons for such bad results. For example, it will take more than 20 minutes to convert a 1024x768 bitmap (I run Centrino 1.8G). When you try to run it on bigger bitmaps, it will take much more time. I've developed my utility to run it on bitmaps with a size of 16X16 pixels. Ok, guys, (thanks a lot to all of you) you are right. After my previous code sample, I've got some e-mails from people who were interested in my TTF convert solution, but they claimed that my code has poor performance. The code used to generate the colours is based on the work of Dan Bruton.This article describes fast bitmap color depth change.This demo was utilised in the paper Teaching Beer’s Law and Absorption Spectrophotometry with a Smart Phone: A Substantially Simplified Protocol by Thomas S. The above tool should been seen as more of an approximation than a rigorous resource. We can see colours which are outside of the gamut of the RGB scheme - there is no unique mapping that definitively converts a wavelength to a colour, and as such However, due to the very complex way in which the eye perceives colours, In this model, each colour is given a value for each red, green and blues components ranging from 0 to 255, giving a total value of 16.7 million possible colours. We can begin to build up a picture of how frequency is related to colour.Ī frequent way of referring to colour on computer screens is by using the RGB system. The lasers in your Blu-ray player emit at 405nm, which as the name suggests, is blue. Helium-neon lasers emit at 632.8nm, which is a bright red. However, a laser for example, emits only at a single very specific frequency. Sunlight appears white to us because it emits almost uniformly over all visible frequencies. Higher frequency radiation, such as x-rays are absorbed by the atmosphere, as are lower frequencies, such as microwaves. The particular range of wavelengths coincides with a window in the Earth's atmosphere, through which this light can travel.

Over the course of millions of years, the human eye has evolved to detect light in the range 380-780nm,Ī portion of the electromagnetic spectrum known as visible light, which we perceive as colour.