Hi, I'm back from vacation and continuing my exploration of ltk. I'm currently trying to build a color picker and I'm modeling it after the blender color picker. To replicate how it looks I need a nice gradient. My first instinct was to just put a bunch of really small rectangles (pixels) on a canvas. This worked (see attachment), but it took about 5 minutes for all the pixels to be put on the canvas. Not ideal, especially if I have to redraw the gradient when the brightness value is changed by some slider or something. My next idea was to use a bitmap. This leads my to my first question: How do I get a bitmap on a canvas? I tried the following code. ``` (defvar image (open "lena_gray.bmp")) (with-ltk () (let* ((canvas (make-instance 'canvas :width 400 :height 400))) (pack canvas) (let ((lena (create-bitmap canvas 20 20 :bitmap image))) (declare (ignore lena))))) ``` And I get a generic type-error: The value NIL is not of type STREAM when binding STREAM [Condition of type TYPE-ERROR]The value NIL is not of type STREAM when binding STREAM [Condition of type TYPE-ERROR] There is really no example given in the documentation. So I need help with this one (Using SBCL on Linux by the way). The next question is concerning transparent colors. To darken the gradient I thought of having an oval over the bitmap, on which I can change the transparency value. I haven't found a way to do that with "itemconfigure". And I also haven't found a place where all the keyword arguments are listed for "itemconfigure". I'm almost certain that there are no transparency options for canvas items in tcl/tk. But in case I've overlooked them, I'm asking anyway. I'd also like to say that I accept tips on my approach. Is there an obvious solution that I'm missing or are there other general tips I need to figure it out myself. Please let me know! Thanks in advance for any help. Greetings, Tom.
