Image Contrast

[David Bovill]

Rob Cozens wrote:
>
> Hi David,
>
>> question about how to script changing the image contrast - you know 
>> with a slider? As far as I can figure there are three ways to go:
>
> How about:
>
> (4) With image "My Image" over a white background
>
> Slider with start value of zero, end value 26, opens with current 
> value 13.
>
> on mouseStillDown
>     set the blendLevel of image "My Image" to the thumbPosition of me
> end mouseStillDown
>
> on mouseUp
>     set the blendLevel of image "My Image" to the thumbPosition of me
> end MouseUp
>
> In my application the actual image changes, and is stored in the 
> card's expandedImage property; so my slider does:
>
> on mouseStillDown
>     get word 2 to -1 of the expandedImage of this card
>     set the blendLevel of image it to the thumbPosition of me
> end mouseStillDown 

Great - had a dream this might be possible last night - you know you are 
in trouble when you start to dream of such things :)

Guess you could use a black background to darken the image - is there 
any difference between this effect and adjusting the velocity of the pixels?

Also guess there is no such trick with "contrast"?

Does the convolve dll allow you to adjust contrast and brightness - what 
would that matrix be - lets have a quick search....