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List: cairo
Subject: Re: [cairo] erasing overlay on GTK drawing area widget.
From: Michael K <vk2bea () yahoo ! com>
Date: 2022-03-30 15:33:04
Message-ID: 387477095.225249.1648654384723 () mail ! yahoo ! com
[Download RAW message or body]
Well, I'll ask the question in a cairo only way then...
Can I overlay text onto a cairo surface and then erase the text without destroying \
the image below?Could I, for example, copy/cache the rectangle under the text \
before writing (using extents to determine the dimensions) so that I could later use \
that to effectively restore the underlying image before writing new text.Is there a \
better / simpler way to do this? thanks
On Wednesday, March 30, 2022, 08:18:10 AM EDT, Emmanuele Bassi <ebassi@gmail.com> \
wrote:
Hi;
if you have questions about GTK, you should use the GNOME Discourse:
https://discourse.gnome.org/tag/gtk
Ciao, Emmanuele.
On Tue, 29 Mar 2022 at 16:45, Michael K <vk2bea@yahoo.com> wrote:
I'm attempting to have two GtkDrawingArea widgets in a GtkOverlay container.
The lower widget is a graph and the top widget shows dynamically changing information \
related to the graph based on the mouse position. I cannot seem to erase the top \
drawing area without wiping out the graph on the bottom drawing area. Is this at all \
possible or am I just doing something wrong ?
--
https://www.bassi.io
[@] ebassi [@gmail.com]
[Attachment #3 (text/html)]
<html><head></head><body><div class="ydp984bd265yahoo-style-wrap" \
style="font-family:Helvetica Neue, Helvetica, Arial, \
sans-serif;font-size:10px;"><div></div> <div dir="ltr" data-setdir="false">Well, \
I'll ask the question in a cairo only way then...</div><div dir="ltr" \
data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Can I overlay text \
onto a cairo surface and then erase the text without destroying the image \
below?</div><div dir="ltr" data-setdir="false">Could I, for example, copy/cache the \
rectangle under the text before writing (using extents to determine the \
dimensions) so that I could later use that to effectively restore the underlying \
image before writing new text.</div><div dir="ltr" data-setdir="false">Is there a \
better / simpler way to do this?</div><div dir="ltr" \
data-setdir="false"><br></div><div dir="ltr" \
data-setdir="false">thanks</div><div><br></div>
</div><div id="yahoo_quoted_9259563598" class="yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, \
sans-serif;font-size:13px;color:#26282a;">
<div>
On Wednesday, March 30, 2022, 08:18:10 AM EDT, Emmanuele Bassi \
<ebassi@gmail.com> wrote: </div>
<div><br></div>
<div><br></div>
<div><div id="yiv6765306305"><div><div \
dir="ltr"><div>Hi;</div><div><br clear="none"></div><div>if you have questions about \
GTK, you should use the GNOME Discourse:</div><div><br clear="none"></div><div><a \
rel="nofollow noopener noreferrer" shape="rect" target="_blank" \
href="https://discourse.gnome.org/tag/gtk">https://discourse.gnome.org/tag/gtk</a></div><div><br \
clear="none"></div><div>Ciao,</div><div> Emmanuele.<br \
clear="none"></div></div><br clear="none"><div id="yiv6765306305yqt20211" \
class="yiv6765306305yqt3775583146"><div class="yiv6765306305gmail_quote"><div \
dir="ltr" class="yiv6765306305gmail_attr">On Tue, 29 Mar 2022 at 16:45, Michael K \
<<a rel="nofollow noopener noreferrer" shape="rect" \
ymailto="mailto:vk2bea@yahoo.com" target="_blank" \
href="mailto:vk2bea@yahoo.com">vk2bea@yahoo.com</a>> wrote:<br \
clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid \
rgb(204,204,204);padding-left:1ex;" class="yiv6765306305gmail_quote"><div><div \
style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:10px;"><div \
dir="ltr">I'm attempting to have two GtkDrawingArea widgets in a GtkOverlay \
container.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">The lower widget \
is a graph and the top widget shows dynamically changing information related to the \
graph based on the mouse position.</div><div dir="ltr"><br clear="none"></div><div \
dir="ltr">I cannot seem to erase the top drawing area without wiping out the graph on \
the bottom drawing area.</div><div dir="ltr"><br clear="none"></div><div dir="ltr">Is \
this at all possible or am I just doing something wrong \
?</div></div></div></blockquote></div></div><br clear="all"><br clear="none">-- <br \
clear="none"><div dir="ltr" class="yiv6765306305gmail_signature"><a rel="nofollow \
noopener noreferrer" shape="rect" target="_blank" \
href="https://www.bassi.io">https://www.bassi.io</a><br clear="none">[@] ebassi [@<a \
rel="nofollow noopener noreferrer" shape="rect" target="_blank" \
href="http://gmail.com">gmail.com</a>]</div> </div></div></div>
</div>
</div></body></html>
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