matthiasm wrote:
>
> On 25.07.2008, at 15:23, Alvin wrote:
>
>> According to the the FLTK manual, Fl_Image::color_average() states:
>> "The original image data is not altered by this method"
>>
>> This is great for what I am doing except I do not know how to have
>> the image
>> draw the "original image data". Basically, how can I remove the
>> saturation?
>>
>> This applies to Fl_Image::desaturate(). It makes the same claim
>> about not
>> altering the original image data.
>
>
> Both functions create a new image that you can use instead of the old
> one, for example. You can then simply delete the old image if you like.
>
> To draw an image, either cal someWidget->image(myImage), which will
> make the image part of the label for that widget, or derive your own
> widget and override the draw() function to draw you custom widgets
> with your own ideas on where the images go.
>
> Matthias
>
>
> ----
> http://robowerk.com/
Hmmm, I don't fully understand. I figured it created a new image, but the
old one is stored in Fl_Image somewhere (perhaps data[1]?) The problem is
the Fl_Image::color_average() doesn't have a return value.
Here's a trivial example:
Fl_Button *b = new Button(......); // Assume b is global
Fl_Shared_Image *img = Fl_Shared_Image::get("/path/to/image.png");
b->image(img);
// now later in the code I want to darken the image
b->image()->color_average(FL_BLACK, 0.4);
// now even later I want to restore the original image
b-> ????
As a work around, I store the original image in b's user_data(). I then make
a copy of the image and call color_average() on the copy. I then set b's
image() to the darkened, copied image. To restore the image, I move the
pointer from user_data() to b->image() after I clean the darkened, copied
image (delete it).
I figured that there would be a way to undo the color_average() and
desaturate() since they do not modify the original image.
--
Alvin
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