Is there a selection widget?

[pyqtgraphuser]

Is there a selection widget that I can add to a plot window. Here is the flow I need to implement:

When the user (presses some key [maybe ctrl]. It can't be the mouse click button since that already controls zoom) and moves the mouse, One vertical infinite line appears and as the mouse gets moved the region selected by the mouse gets highlighted. When the key is released a handler is called with the selected x, y (in data points) coordinates of the selected region. Using this, I would open another pyqtgraph window with more detailed charts for the selected region. 

[megan kratz]

On Sat, Mar 31, 2012 at 10:22 AM, pyqtgraphuser <webus...@gmail.com> wrote:

Is there a selection widget that I can add to a plot window. Here is the flow I need to implement:

When the user (presses some key [maybe ctrl]. It can't be the mouse click button since that already controls zoom) and moves the mouse, One vertical infinite line appears and as the mouse gets moved the region selected by the mouse gets highlighted. When the key is released a handler is called with the selected x, y (in data points) coordinates of the selected region. Using this, I would open another pyqtgraph window with more detailed charts for the selected region. 

What you want sounds a lot like a LinearRegionItem. I don't think there are methods yet for adding them to the plot using the mouse in the way you described, but aside from that they can do what you're describing. Once a LinearRegionItem is added to a plot, it is movable with the mouse, so you can still adjust it's position that way.

For an example of how to use a LinearRegionItem to select data in one plot to be re-plotted in another plot see pyqtgraph/examples/Plotting.py, particularly plots 8 & 9 (line 73 -86). This file can be run on it's own to give you a sense of how LinearRegionItems act.

Cheers,

Megan

[Luke Campagnola]

On Sat, Mar 31, 2012 at 11:46, megan kratz <megan...@gmail.com> wrote:

On Sat, Mar 31, 2012 at 10:22 AM, pyqtgraphuser <webus...@gmail.com> wrote:

Is there a selection widget that I can add to a plot window. Here is the flow I need to implement:

When the user (presses some key [maybe ctrl]. It can't be the mouse click button since that already controls zoom) and moves the mouse, One vertical infinite line appears and as the mouse gets moved the region selected by the mouse gets highlighted. When the key is released a handler is called with the selected x, y (in data points) coordinates of the selected region. Using this, I would open another pyqtgraph window with more detailed charts for the selected region. 

What you want sounds a lot like a LinearRegionItem.

I'll agree with Megan and add that you would need to extend the mouseDragEvent method for the plot's ViewBox to implement this functionality. Here's a simple example (use ctrl-drag to set the region):

import pyqtgraph as pg

from PyQt4 import QtCore

pw = pg.plot()

lr = pg.LinearRegionItem()

lr.hide()

pw.addItem(lr)

vb = pw.plotItem.vb  ## get the viewbox from the plot item

def drag(ev):

    global vb, lr

    if (ev.button() == QtCore.Qt.LeftButton) and (ev.modifiers() & QtCore.Qt.ControlModifier):

        lr.show()

        lr.setRegion([vb.mapToView(ev.buttonDownPos()).x(), vb.mapToView(ev.pos()).x()])

        ev.accept()

    else:

        pg.ViewBox.mouseDragEvent(vb, ev)

vb.mouseDragEvent = drag

[pyqtgraphuser]

> I'll agree with Megan and add that you would need to extend the
> mouseDragEvent method for the plot's ViewBox to implement this
> functionality. Here's a simple example (use ctrl-drag to set the region):

Thanks. How would I open the selected region in a completely new plot
window?

[Luke Campagnola]

On Tuesday, April 10, 2012 5:26:01 AM UTC-4, pyqtgraphuser wrote:

Thanks. How would I open the selected region in a completely new plot
window?

This is just a repeat of code you've already used--Create a new plot by any method (pg.plot(), pg.PlotWidget, GraphicsLayout.addPlot, etc.) then plot your data there and set the bounds with the setRange method. 

[pyqtgraphuser]

This is just a repeat of code you've already used--Create a new plot by any method (pg.plot(), pg.PlotWidget, GraphicsLayout.addPlot, etc.) then plot your data there and set the bounds with the setRange method. 

Ok I get it now. here is the example code I have so far. How do I capture a key release event (some way to capture release of the ctrl key) on the viewbox. I tried this and did not work:

def release(ev):

   #somehow capture release 

    win = pg.GraphicsWindow()

    label = pg.LabelItem(justify='right')

    win.addItem(label)

    p1 = win.addPlot(row=1, col=0)

    p1.plot(data1, pen="r")

vb.keyReleaseEvent = release

Full working example as a hack to just demonstrate open a new window:

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

import initExample ## Add path to library (just for examples; you do not need this)

import numpy as np

import pyqtgraph as pg

from pyqtgraph.Qt import QtGui, QtCore

from pyqtgraph.Point import Point

#genearte layout

app = QtGui.QApplication([])

win = pg.GraphicsWindow()

p1 = win.addPlot(row=1, col=0)

data1 = 10000 + 3000 * np.random.random(size=10000)

p1.plot(data1, pen="r")

lr = pg.LinearRegionItem()

lr.hide()

p1.addItem(lr)

vb = p1.vb  ## get the viewbox from the plot item

count = 0

def drag(ev):

    global vb, lr, count

    if (ev.button() == QtCore.Qt.LeftButton) and (ev.modifiers() & QtCore.Qt.ControlModifier):

        lr.show()

        lr.setRegion([vb.mapToView(ev.buttonDownPos()).x(), vb.mapToView(ev.pos()).x()])

        ev.accept()

        count = count + 1

        if count == 40:

            win = pg.GraphicsWindow()

            label = pg.LabelItem(justify='right')

            win.addItem(label)

            p1 = win.addPlot(row=1, col=0)

            p1.plot(data1, pen="r")

    else:

        pg.ViewBox.mouseDragEvent(vb, ev)

vb.mouseDragEvent = drag

## Start Qt event loop unless running in interactive mode or using pyside.

import sys

if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):

    app.exec_()

[Luke Campagnola]

On Sun, Apr 15, 2012 at 08:04, pyqtgraphuser <webus...@gmail.com> wrote:

Ok I get it now. here is the example code I have so far. How do I capture a key release event (some way to capture release of the ctrl key) on the viewbox. I tried this and did not work:

def release(ev):

   #somehow capture release 

    win = pg.GraphicsWindow()

    label = pg.LabelItem(justify='right')

    win.addItem(label)

    p1 = win.addPlot(row=1, col=0)

    p1.plot(data1, pen="r")

vb.keyReleaseEvent = release

Aha.. I have fixed a bug that was preventing the scene from giving keyboard focus to the ViewBox. You can download the latest or just merge in the changes from rev. 80.

From a user interaction perspective, I think it would be more natural to open the window when the mouse is released, rather than the ctrl button (but this is just my preference and either option should work).

Luke

[pyqtgraphuser]

From a user interaction perspective, I think it would be more natural to open the window when the mouse is released, rather than the ctrl button (but this is just my preference and either option should work).

How would I do that? I tried:

vb.mouseReleaseEvent = release

and it does not fire when I release the mouse.  

[Luke Campagnola]

I added some new documentation!

Since you're using mouseDragEvent, you can just check to see whether the drag has finished:

http://luke.campagnola.me/code/pyqtgraph/documentation/graphicsscene/mousedragevent.html#pyqtgraph.GraphicsScene.mouseEvents.MouseDragEvent.isFinish

There's also more information about how pyqtgraph's mouse system works with Qt's mouse system (and why there needed to be two mouse systems to begin with):

http://luke.campagnola.me/code/pyqtgraph/documentation/graphicsscene/graphicsscene.html

 

[Pedro Paiva]

Hello, I was trying to implement the code below on a viewBox itself (from a 2D plot, not a regular one)
But I'm failing..., I think the linear region is being displayed below my image and not above... =/

Any suggestions?

[Luke Campagnola]

On Mon, Jul 8, 2013 at 5:47 AM, Pedro Paiva <p3k...@gmail.com> wrote:

Hello, I was trying to implement the code below on a viewBox itself (from a 2D plot, not a regular one)
But I'm failing..., I think the linear region is being displayed below my image and not above... =/

Any suggestions?

All QGraphicsItem subclasses inherit the methods 'zValue' and 'setZValue', which determine the order in which items are drawn. 

http://qt-project.org/doc/qt-4.8/qgraphicsitem.html#setZValue

Does this solve your problem?

Luke

 

Em domingo, 1 de abril de 2012 02h21min18s UTC+1, Luke Campagnola escreveu:

import pyqtgraph as pg

from PyQt4 import QtCore

pw = pg.plot()

lr = pg.LinearRegionItem()

lr.hide()

pw.addItem(lr)

vb = pw.plotItem.vb  ## get the viewbox from the plot item

def drag(ev):

    global vb, lr

    if (ev.button() == QtCore.Qt.LeftButton) and (ev.modifiers() & QtCore.Qt.ControlModifier):

        lr.show()

        lr.setRegion([vb.mapToView(ev.buttonDownPos()).x(), vb.mapToView(ev.pos()).x()])

        ev.accept()

    else:

        pg.ViewBox.mouseDragEvent(vb, ev)

vb.mouseDragEvent = drag

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[Pedro Paiva]

It partially helps... xP
Now it's in front but it's not really a box-region but an infinity one (see image) and is permanent... (if I use .hide() it doesn't show at all)

Here's my code:

    def mouseDragEvent(self, ev):

        if ev.button() == Qt.RightButton:

            ev.ignore()

        else:

#             Make region appear

            region = pg.LinearRegionItem()

            region.setZValue(99)

            self.addItem(region)

            region.setRegion([ self.mapToView(ev.buttonDownPos()).x(), self.mapToView(ev.pos()).x() ])

            pg.ViewBox.mouseDragEvent(self, ev)

with self being a ViewBox

[megan kratz]

LinearRegionItem is meant to be infinite in one direction. For a "box-region", you might try pg.RectROI or QtGui.QGraphicsRectItem.

[Luke Campagnola]

On Mon, Jul 8, 2013 at 11:34 AM, Pedro Paiva <p3k...@gmail.com> wrote:

It partially helps... xP
Now it's in front but it's not really a box-region but an infinity one (see image) and is permanent... (if I use .hide() it doesn't show at all)

Here's my code:

    def mouseDragEvent(self, ev):

        if ev.button() == Qt.RightButton:

            ev.ignore()

        else:

#             Make region appear

            region = pg.LinearRegionItem()

            region.setZValue(99)

            self.addItem(region)

            region.setRegion([ self.mapToView(ev.buttonDownPos()).x(), self.mapToView(ev.pos()).x() ])

            pg.ViewBox.mouseDragEvent(self, ev)

with self being a ViewBox

Perhaps we should back up--what exactly are you trying to achieve with this? If you want to do a 2D region-of-interest analysis, then LinearRegionItem will not help; as you have discovered it is for 1D selection. See pyqtgraph/examples/ROIExamples.py for some 2D analysis tools. If you want to drag a rubber-band to zoom in on the image, then see http://pyqtgraph.org/documentation/graphicsItems/viewbox.html#pyqtgraph.ViewBox.setMouseMode

 

[Pedro Paiva]

hmm... I see...

Well, I was trying to implement that because the RectMode doesn't show the selected region... (I'm currently using RectMode as well)

Another question about ViewBox (sorry if it's not completely related, I just don't think it's appropriate to just go creating new topics all the time... xP)
But how can I identify the items of a ViewBox? With the .allChildren() I can see all of them, but I have multiple ImageItems that I can't keep track of the items themselves (just the data inside as they are loaded by the user) but I would like to change their opacity, zlevel and data itself... (and the same with HistogramLUTItem)

Best regards,

Pedro Paiva

[Luke Campagnola]

On Wed, Jul 10, 2013 at 6:07 AM, Pedro Paiva <p3k...@gmail.com> wrote:

Well, I was trying to implement that because the RectMode doesn't show the selected region... (I'm currently using RectMode as well)

Can you explain this further? Under what circumstances does RectMode not work?

 

Another question about ViewBox (sorry if it's not completely related, I just don't think it's appropriate to just go creating new topics all the time... xP)
But how can I identify the items of a ViewBox? With the .allChildren() I can see all of them, but I have multiple ImageItems that I can't keep track of the items themselves (just the data inside as they are loaded by the user) but I would like to change their opacity, zlevel and data itself... (and the same with HistogramLUTItem)

Sorry, I don't follow. What is wrong with allChildren(), and why can't you keep track of the items? 

Luke

[Pedro Paiva]

Em quarta-feira, 10 de julho de 2013 15h53min11s UTC+1, Luke Campagnola escreveu:

On Wed, Jul 10, 2013 at 6:07 AM, Pedro Paiva <p3k...@gmail.com> wrote:

Well, I was trying to implement that because the RectMode doesn't show the selected region... (I'm currently using RectMode as well)

Can you explain this further? Under what circumstances does RectMode not work?

RectMode doesn't show the area being selected (while dragging the mouse)

 

 

Another question about ViewBox (sorry if it's not completely related, I just don't think it's appropriate to just go creating new topics all the time... xP)
But how can I identify the items of a ViewBox? With the .allChildren() I can see all of them, but I have multiple ImageItems that I can't keep track of the items themselves (just the data inside as they are loaded by the user) but I would like to change their opacity, zlevel and data itself... (and the same with HistogramLUTItem)

Sorry, I don't follow. What is wrong with allChildren(), and why can't you keep track of the items? 

allChildren() returns everything inside a ViewBox and if I have several images in there I didn't know wich is wich...

Now I'm adding a marker in every image as img.setData(0, 'img name') so when I ask for the children I also check img.data(0) to match the name and then find the children I need to work with...

[Luke Campagnola]

On Wed, Jul 10, 2013 at 11:57 AM, Pedro Paiva <p3k...@gmail.com> wrote:

Em quarta-feira, 10 de julho de 2013 15h53min11s UTC+1, Luke Campagnola escreveu:

On Wed, Jul 10, 2013 at 6:07 AM, Pedro Paiva <p3k...@gmail.com> wrote:

Well, I was trying to implement that because the RectMode doesn't show the selected region... (I'm currently using RectMode as well)

Can you explain this further? Under what circumstances does RectMode not work?

RectMode doesn't show the area being selected (while dragging the mouse)

Ah, there's a bug: set the Z-value of the selection rectangle to be very large:

viewbox.rbScaleBox.setZValue(1e9)

Or alternatively, set the Z-value of your image to be lower.

 

 

Another question about ViewBox (sorry if it's not completely related, I just don't think it's appropriate to just go creating new topics all the time... xP)
But how can I identify the items of a ViewBox? With the .allChildren() I can see all of them, but I have multiple ImageItems that I can't keep track of the items themselves (just the data inside as they are loaded by the user) but I would like to change their opacity, zlevel and data itself... (and the same with HistogramLUTItem)

Sorry, I don't follow. What is wrong with allChildren(), and why can't you keep track of the items? 

allChildren() returns everything inside a ViewBox and if I have several images in there I didn't know wich is wich...

Now I'm adding a marker in every image as img.setData(0, 'img name') so when I ask for the children I also check img.data(0) to match the name and then find the children I need to work with...

That is a reasonable solution. We generally don't need to use the clumsy Qt setData methods, though, since this is python and we can set any dynamic attributes we want:  img.name = "...". The reverse approach is to just maintain a dictionary {'name": img} that updates whenever the user adds another image. Or if you have a set of Parameter instances that correspond to the image, you can just set param.image = img. ..but otherwise there is no way for pyqtgraph to keep track of the images for you; all it knows is that you have added images to the view.

Luke

[Pedro Paiva]

Nice! xD
Just saved me a few lines creating dragHLines/dragVLines for the zoom... xD


Thx!