ltk-user

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259 discussions

19 Aug '19

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.

3 4

This documentation is quite confusing.
by Tom Hassel 09 Aug '19

09 Aug '19

I've been getting into ltk, since I wanted to do some GUI programming again. I'm currently trying some things, one of them being changing the color of a button. This should be possible becaus of this bit of documentation <http://www.peter-herth.de/ltk/ltkdoc/node18.html>. But it is not really specified how I could do it. I've tried with 'configure' and I tried in the initialization code and even in the 'pack' function, but it does not seem to work. It might be nice if the documentation told me how to do this. The working code looks like this. How do I change the color of the button? ``` (with-ltk () (let* ((frame (make-instance 'frame)) (button (make-instance 'button :master frame :text "Hello, World" :command (lambda () (print "Hello, World"))))) (pack frame) (pack button))) ``` Thanks in advance for any help. Greetings, Tom

3 5

[ANN] nodgui
by cage 11 Dec '18

11 Dec '18

Hello! I think my attempt to clean up ltk went a bit too far, and nodgui was born. :) This library is basically a refactoring of ltk with a bit of modernization (use some new wish 8.6 features) and some syntactic sugar on top (and probably some bugs too :) ). More information can be found on the README here: https://notabug.org/cage/nodgui/raw/master/README.txt the repository can be found here instead: https://notabug.org/cage/nodgui I do not mean in anyway this fork as hostile, the work of the people behind ltk (and Peter in particular) was fantastic and my library is just a simple attempt to take care of a piece code that helped me a lot in the last years. Of course the library is still FLOSS (LLGPL licensed) so anyone is very welcome to contribute (there is a lot of work to do)! Bye! C.

1 0

patch proposal
by cage 18 Nov '18

18 Nov '18

Hi Peter! I have a patch for ltk that supposed to do the following: - remove use of a deprecated function for sbcl: "sb-debug:backtrace" https://github.com/herth/ltk/blob/master/ltk/ltk.lisp#L5088 with "sb-debug:print-backtrace" - prevent ltk to "leak" error messages from other applications (I have had problems with font-config, for example) into the communication pipe with user application, this pollute the messages sent on the pipe and makes the application crash. I have just added ":error nil" to this line https://github.com/herth/ltk/blob/master/ltk/ltk.lisp#L464 i feel this solution is sub-optimal as is not portable, probably UIOP could help here. - clean a bit the code (mostly comes from Emacs for free ;-) ) Please can you tel me how can I send the patch to be reviewed? Is here a good place or should I set up a pull request on github? Bye! C.

1 0

menu of ltk
by Kamuy Cikap 21 Jul '18

21 Jul '18

Hi everyone. I have a question. There is check button and radio button in Tcl/Tk8.4 in menu. is there check button and radio button in menu widget of LTK? I looked ltktest in ltk.lisp source code. I found make - menu and "make-menubutton". Furthermore I found "add-separator". Is there a check button or radio button in the same way? Please Tell me this code.

3 3

Use of postcommand in combobox?
by Volker 11 Jul '18

11 Jul '18

Has anyone a clue how postcommand in combobox is supposed to be used? I want to construct the values of a combobox according to the state of a device just when klicking on the widget. I can construct a combobox: (defun combo-1 () (ltk:with-ltk () (let ((c (make-instance 'combobox :text "Values:" :values '(1 2 3)))) (ltk:pack c :side :left :padx 2)))) and change the values outside the constructor: (defun combo-values () "Change :values of combobox outside the constructor" (ltk:with-ltk () (let ((c (make-instance 'combobox :text "Values:"))) (ltk:pack c :side :left :padx 2) (setf (options c) '(1 2 3))))) ; changes field :values Even if I think it would have been better if this would have worked instead: (setf (values c) '(1 2 3)) But fail when I try to use postcommand. This doesn't work: (defun combo-postcommand-1 () "Use of postcommand in combobox." (ltk:with-ltk () (let ((c (make-instance 'combobox :text "Values:" :postcommand (lambda () (set (options c) '(1 2 3)))))) (ltk:pack c :side :left :padx 2)))) (I understand that c is not defined when the lambda command is read but don't see a correct solution.) I can not even run a simple function as postcommand, because this doesn't work either: (defun combo-postcommand-2 () (ltk:with-ltk () (let ((c (make-instance 'combobox :text "Values:" :postcommand (lambda () (format t "Run postcommand~%"))))) (ltk:pack c :side :left :padx 2)))) ???

3 8

How to change the title of the root window?
by Volker 23 Jun '18

23 Jun '18

I'm trying to get started with ltk and of cause running into many problems. One is: how do I change the title of the root window (it is "LTK" as default). The corresponding python code would be: root = Tk() root.title("Hello, world") This was one of my many unsuccessful tries: (defun how-to-set-title () (ltk:with-ltk () (let* ((root (make-instance 'ltk:widget :name "." :path ".")) (b (make-instance 'button :master nil :text "Press Me" :command (lambda () (format t "Hello World!~&"))))) (setf (title root) "My app") (pack b)))) I experienced a bit with toplevel (where I could set the name of the window) but this always opened an additional new window. Any help appreciated! Regards Volker

2 3

I want to control on and off ob check-button.
by Kamuy Cikap 01 Jun '18

01 Jun '18

Hi every one. I want to control on and off of check-button by clicking the button. but I can't it. how do control it? code point is _ (setf (value cbtn1) "ON")))) ;; <- I want control on and of. in the my code. Please help me. This is the my code. ;;;;;; my code ;;; LTKでボタンを表示する (ql:quickload :ltk) ;; my package (defpackage :ex4-05 (:use :common-lisp :common-lisp-user :ltk) (:export :main)) (in-package :ex4-05) (defun main () (with-ltk () (let* ( (cbtn1 (make-instance 'check-button :text "check button1" :variable :cbtn1_val :onvalue :on :offvalue :off :command (lambda (value) (format t "check-button1:~A~%" value) ))) (cbtn2 (make-instance 'check-button :text "check button2")) (cbtn3 (make-instance 'check-button :text "Close")) (btn (make-instance 'button :text "check on!" :command (lambda () (setf (value cbtn1) "ON")))) ;; <- I want control on and of. ) (pack (list cbtn1 cbtn2 cbtn3) :side :top :fill :both :expand :yes) (pack btn :side :top :fill :both :expand :yes) ))) (main)

3 3

Set height of a scrolled-canvas
by Luis López 11 Sep '17

11 Sep '17

Hi! I'm trying to simulate a diffraction grating for my pupils. I have two scrolled-canvas: one for displaying the spectrum as colors, and one for showing its intensity profile. The problem is that I want to make the first one to have a specific height (no matter if the window gets maximized), and the other to get expanded, but all I can get is the two having always the same height. What am I doing wrong? Thank you very much, Luis

2 3

ltk patch for SBCL
by Douglas Katzman 21 Apr '17

21 Apr '17

Please apply the following forward-and-backward compatible diff for SBCL. closure-header-widetag is pending removed in the next release. diff --git a/ginspect.lisp b/ginspect.lisp index 3d448f8..a5ad37d 100644 --- a/ginspect.lisp +++ b/ginspect.lisp @@ -252,8 +252,7 @@ (inspected-standard-object-elements object))) #+:sbcl (defmethod inspected-parts ((object function)) - (let* ((type (sb-kernel:widetag-of object)) - (object (if (= type sb-vm:closure-header-widetag) + (let ((object (if (sb-kernel:closurep object) (sb-kernel:%closure-fun object) object))) (values (format nil "FUNCTION ~S.~@[~%Argument List: ~A~]." object

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