The easiest way to do this is to use the text:line-numbers-mixin in the
framework. Here's an example of an editor with line numbers:
#lang racket
(require racket/gui framework)
(define text (new (text:line-numbers-mixin text:standard-style-list%)))
(define frame
(new frame%
[label "editor with line numbers"]
[height 500]
[width 500]))
(define editor (new editor-canvas% [parent frame] [editor text]))
(send text show-line-numbers! #t)
(send frame show #t)
On Wed, Mar 8, 2017 at 8:09 PM, WarGrey Gyoudmon Ju <juzhenli...@gmail.com>
wrote:
> Sorry for so many small mails on one topic.
>
> In my current project, I implements something similar to line numbers.
> At the beginning, I separate them into different canvases so that the GUI
> behaves like iTunes(later I found that they do not implement it in a
> consistent way), but now I like the way that racket already provides, to
> override the (on-paint) method of text%, its first argument gives the
> change to draw something before or after the text% itself is displayed.
>
> On Thu, Mar 9, 2017 at 9:51 AM, WarGrey Gyoudmon Ju <juzhenli...@gmail.com
> > wrote:
>
>> Okay, in the gui framework, there is an interface text:line-numbers<%>
>>
>> On Thu, Mar 9, 2017 at 9:46 AM, WarGrey Gyoudmon Ju <
>> juzhenli...@gmail.com> wrote:
>>
>>> But sometimes I happened to see that some one-line codes and their line
>>> number are overlapped.
>>> And line numbers are also controlled by the same horizontal scrollbar(I
>>> mean, it is contained in the scrollbar's view, if there is another canvas
>>> this should not happen).
>>>
>>> Maybe they are displayed in a special image box(also, those non-string
>>> snips may produce lines that bigger than text line height).
>>>
>>> On Thu, Mar 9, 2017 at 9:31 AM, WarGrey Gyoudmon Ju <
>>> juzhenli...@gmail.com> wrote:
>>>
>>>> I think, line numbers are likely displayed in another canvas.
>>>> The current implementation of text% does not support advanced font
>>>> features, the line height therefore is always the same. Displaying the line
>>>> numbers just consists of a bit of arithmetic.
>>>>
>>>> On Thu, Mar 9, 2017 at 8:31 AM, 武晓宇 <guluguluc...@gmail.com> wrote:
>>>>
>>>>> I want to implement a text% object. And display the line number when
>>>>> string is inserted the text/canvas area.
>>>>> Like the DrRacket IDE in "show line number" mode.
>>>>> I read the source code of DrRacket but do not find the answer. Could
>>>>> anyone give a hand?
>>>>>
>>>>> --
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>>>>>
>>>>
>>>>
>>>
>>
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