visualpython-users

[Visualpython-users] Mouse (x,y) in a graph

[Bruce S. <bas...@un...>]

Here is a little program that plots a graph and displays (x,y) whenever the
left mouse button is down.

from visual.graph import *

oscillation = gdisplay(title='Test Plotting', xtitle='Time',
ytitle='Response')
funct1 = gcurve(color=color.cyan)
funct2 = gvbars(color=color.red, delta=0.8)
funct3 = gdots(color=color.yellow)

for t in arange(-30, 76, 1):
    funct1.plot(pos=(t, 5.0+5.0*cos(-0.2*t)*exp(0.015*t)) )
    funct2.plot(pos=(t, 2.0+5.0*cos(-0.1*t)*exp(0.015*t)) )
    funct3.plot(pos=(t, 5.0*cos(-0.03*t)*exp(0.015*t)) )

showxy = label(display=oscillation.display, yoffset=10, line=0, opacity=1,
visible=0)
while 1:
    rate(300)
    m = oscillation.display.mouse
    if m.button == 'left':
        showxy.pos = (m.pos.x,m.pos.y)
        showxy.text = '%d,%d' % (m.pos.x,m.pos.y)
        showxy.visible = 1
    else:
        showxy.visible = 0

[Visualpython-users] A better mousetrap

[Bruce S. <bas...@un...>]

Having thought about it overnight, here's a significantly better mouse
routine for graphing. It displays crosshairs as you drag the mouse. And just
in case the mailer doesn't preserve tabs correctly, I also attach a copy of
the file.

Bruce Sherwood

--------------------------------------------------

from visual.graph import *

oscillation = gdisplay(title='Test Plotting', xtitle='Time',
ytitle='Response')

funct1 = gcurve(color=color.cyan)
funct2 = gvbars(color=color.red, delta=0.8)
funct3 = gdots(color=color.yellow)

for t in arange(-30, 76, 1):
    funct1.plot(pos=(t, 5.0+5.0*cos(-0.2*t)*exp(0.015*t)) )
    funct2.plot(pos=(t, 2.0+5.0*cos(-0.1*t)*exp(0.015*t)) )
    funct3.plot(pos=(t, 5.0*cos(-0.03*t)*exp(0.015*t)) )

showxy = label(display=oscillation.display, yoffset=10, line=0, opacity=1,
visible=0)
gray = (0.5,0.5,0.5)
hor = curve(display=oscillation.display, color=gray, visible=0)
vert = curve(display=oscillation.display, color=gray, visible=0)
pos = None
while 1:
    status = oscillation.display.mouse
    if status.events:
        m = status.getevent()
        if m.press == 'left':
            pos = status.pos
            showxy.visible = 1
            disp = oscillation.display
            xmax = disp.range.x
            ymax = disp.range.y
            xcenter = disp.center.x
            ycenter = disp.center.y
            hor.visible = 1
            vert.visible = 1
        elif m.release == 'left':
            pos = None
            showxy.visible = 0
            hor.visible = 0
            vert.visible = 0
    if pos and (pos is not status.pos):
        showxy.pos = pos = status.pos
        hor.pos = [(xcenter-xmax,pos.y),(xcenter+xmax,pos.y)]
        vert.pos = [(pos.x,ycenter-ymax),(pos.x,ycenter+ymax)]
        showxy.text = '%0.3g,%0.3g' % (status.pos.x,status.pos.y)

[Visualpython-users] Re: plotting many dots

[Bruce S. <bas...@un...>]

Thanks to the issues raised about plotting lots of dots in visual.graph, I
can see more clearly why we need (at the least) a "points" object, very
similar to the curve object (maybe even an option for the curve object). In
plotting large amounts of data as points, currently each point must be a
separate object, which uses up lots of memory. It is also presumably
expensive to run through all those objects in each Visual window update.
(Visual paints the picture from scratch each time -- there is no attempt to
figure out which part of the scene has changed.)

The points object would be very similar to the curve object, but it wouldn't
draw lines between the points of the curve. There is an issue that with the
curve object, when there get to be too many points, intermediate points are
dropped for performance reasons. That's not tenable with data points (and
for that matter causes display problems with curve in some cases, too).
Probably there needs to be some programmer control over this, if the
plotting of lots of data is to be made feasible.

Comments? Suggestions?

Bruce Sherwood