cHiddenImageData vs imageData

Earthednet-wp prothero at earthednet.org
Sun Oct 20 01:39:47 EDT 2013


Paul,
Thanks! I see that the setting of the custom property cHiddenImageData is covered in the later tutorial where converting an image to greyscale is covered. So, for those that start st earlier tutorials, that would be missed. The tutorial in setting a threshold, where I looked to see how yo modify images, is missing that critical step.

Thanks again. 
Best,
Bill

William Prothero
http://es.earthednet.org

> On Oct 19, 2013, at 6:40 PM, Paul Hibbert <paulhibbert at mac.com> wrote:
> 
> Hi Bill,
> 
> The cHiddenImageData is a Custom Property used to temporarily store the imageData. The "c" prefix gives it away once you get to understand the logic for naming variables & properties etc. See P.165 of the User Guide (if you can find it!).
> 
> Quote from the LC webpage "Vision: How do I Convert a Color Image to Grayscale?"
> 
> You also have to create the custom property cHiddenImageData for the Image Area. This is used in a subsequent lessons in which it is necessary to have a copy of the image that is being updated.
> 
> Hope this helps,
> 
> Paul
> 
>> On 2013-10-19, at 5:35 PM, prothero at earthednet.org wrote:
>> 
>> I'm drawing symbols on an image. The live code tutorial give examples that use 
>> the cHiddenImageData of image "image"
>> The cHiddenImageData seems to place my changes all along the left side of the image. If I use "the image data", I get reasonable placements for my symbols.
>> 
>> There is no entry in the documents (6.2.2) for cHiddenImageData. What is it? Why would it be used instead of the plain image data?
>> 
>> Thanks,
>> Bill
>> 
>> William Prothero
>> http://es.earthednet.org
>> 
>> 
>> 
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