I'll look into this. Just FYI, this works fine when OpenGL is disabled by passing opengl=FALSE to qplotView(). Need to get this working with GL.<br><br>Michael<br><br><div class="gmail_quote">On Wed, Oct 20, 2010 at 3:18 PM, Yihui Xie <span dir="ltr"><<a href="mailto:xieyihui@gmail.com">xieyihui@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi,<br>
<br>
I want to define a glyph which is a short segment as follows, but when<br>
the slope b=0, the glyph looks weird on screen (it is a filled<br>
square); other slopes are fine. I don't know what's going on:<br>
<br>
library(qtpaint)<br>
## x: length; b: slope<br>
qglyphSegment <- function(x = 5, b = 0) {<br>
glyph <- Qt$QPainterPath()<br>
x0 <- x * cos(atan(b))<br>
y0 <- x * sin(atan(b))<br>
glyph$moveTo(-x0, -y0)<br>
glyph$lineTo(x0, y0)<br>
# glyph$closeSubpath()<br>
glyph<br>
}<br>
<br>
s <- qscene()<br>
test_layer <- qlayer(s, function(layer, painter) {<br>
qdrawGlyph(painter, qglyphSegment(), 1:10, .5, stroke = 'black')<br>
qdrawGlyph(painter, qglyphSegment(10, 1), 1:10, .7, stroke = 'black')<br>
qdrawGlyph(painter, qglyphSegment(10, -1), 1:10, .3, stroke = 'black')<br>
}, limits=qrect(0,0,11,1))<br>
qplotView(s)<br>
## see the screenshot attached<br>
<br>
<br>
Thanks!<br>
<br>
Regards,<br>
Yihui<br>
<font color="#888888">--<br>
Yihui Xie <<a href="mailto:xieyihui@gmail.com">xieyihui@gmail.com</a>><br>
Phone: 515-294-2465 Web: <a href="http://yihui.name" target="_blank">http://yihui.name</a><br>
Department of Statistics, Iowa State University<br>
2215 Snedecor Hall, Ames, IA<br>
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<br></blockquote></div><br>