Hi
1/ not all browsers supports such big canvas (but OK, this is browsers
issue), but one need to work around it
2/ the optimalization you describe is implied (paint only what you
need), never the less.. you still have to create unnecessary elements
(overflow hidden? didn't you mean scroll?)
3/ sure... i can somehow do that... but do we need element.textContent?
querySelector API? HTML5 forms? and lot of other new stuff we get? No,
we can do them using some libraries... but we have, because it makes
programming easier...
Essentially... if there are no plans for that, fine :), I can imagine
there is too much work to be done on other issues, but "we can do it
using more elements and more programming" is not an argument...
I was not asking how to do that, I know how... I was asking whether
there is a plan to add scrollbar to canvas.
Brona Klucka
On 20.10.2011 17:17, Robert Eisele wrote:
Hi,
what is wrong with a 100k x 100k canvas? Just draw on the currently
visible region with some overlapping to make slow event listeners not
a problem. This tends to another optimization: Create scrollbars of
the dimension you need and draw on a very small canvas only the
information that is really necessary. Why should you update all the
invisible pixels?
I would say, this problem can be solved simply with JavaScript +
overflow:hidden and doesn't need an extension of the canvas element in
any way.
Robert Eisele
2011/10/20 Bronislav Klučka <bronislav.klu...@bauglir.com
<mailto:bronislav.klu...@bauglir.com>>
On 20.10.2011 14:35, João Eiras wrote:
On Thu, 20 Oct 2011 14:14:12 +0200, Bronislav Klučka
<bronislav.klu...@bauglir.com
<mailto:bronislav.klu...@bauglir.com>> wrote:
Hello,
Would it be possible to extend canvas specification to
include scroll bar functionality? To add scroll bar, to
manage scroll bar (total size, page size). Creating
control based on canvas that needs scrollbar at this point
is unnecessarily difficult at this point.
Brona Klucka
Which is your use case ?
It doesn't make any sense at all to me to have scrollbars in a
canvas. However, if you need scrolling, you can wrap the
canvas with an element with specified dimensions and
overflow:auto.
Hi,
1/ your solution is very wrong solution.... could you imagine
canvas 100000x100000px? well not possible, only solution is to
create smaller canvas, wrap it into overflow auto div with inner
div and then compute the dimension of whole image with javascript
and transfer it to inner div dimensions (so scrollbars would
match) and listen to onScroll event of outer div, and repaint the
image with shifted origin
2/ use cases?
a)
diagram modeller
http://www.webnt.cz/demos/033_canvas_diagram/
what if I have some large diagram?
b) how about creating user controls using canvas? (rich controls
are better doing this way, one has pixel perfect control, full
browser compatibility) like document viewer, rich
listview/treeview control...
Brona Klucka
