graphicsView.fitInView() :- one axis only ?

[JackDinn]

HI all,

This is my fist post here so iv a couple of questions,

My first question is when using fitInView() is there a way to fit just the Y axis and leave the X axis as it is in the position it is ?

Im wanting to have a graph that scrolls along the x axis but is always fit to the size of the graphicsView y axis.

I can build a demo to show exactly what im after if required but im kinda hopping its a simple answer.

Second, when posting code on this forum is it ok to post PyQt4 (Python) as thats what im using ?

[high_flyer]

I don't see this option with fitInView() but you can just use scale, and give 1.0 to the x axis.

[JackDinn]

hmm, yea. but i would need to figure out the y axis scale every time the graphicsView or main window is resised ?

I was trying with this kinda thing :-

rr=ui.graphicsView.mapToScene(ui.graphicsView.frameRect())
left=rr.boundingRect().left()
width=rr.boundingRect().width()
ui.graphicsView.fitInView(left,0,width,300)

rr=ui.graphicsView.mapToScene(ui.graphicsView.frameRect())
left=rr.boundingRect().left()
width=rr.boundingRect().width()
ui.graphicsView.fitInView(left,0,width,300)

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but theres something wrong with it. Every time it runs this bit of code the x axis shrinks a tiny bit i think it is either mapToScene(ui.graphicsView.frameRect()) is not exact enough or theres a rounding problem with the floating value.

I shall have a play with scaling, see what i can see.

cheers.

[JackDinn]

well iv tried everything my small amount of Qt4 knowledge will stretch to including the suggestion above but i just cant get this working.

Iv made a proper demo so people can easily have a look.

#-------------------------------------------------------------------------------
# Name:        module1
# Purpose:
#
# Author:      User
#
# Created:     20/02/2011
# Copyright:   (c) User 2011
# Licence:     <your licence>
#-------------------------------------------------------------------------------
#!/usr/bin/env python
import sys
from PyQt4 import QtCore, QtGui
 
class Ui_MainWindow(QtGui.QMainWindow):
    def setupUi(self, ui):
        ui.resize(600, 400)
        self.centralwidget = QtGui.QWidget(ui)
        self.horizontalLayout = QtGui.QHBoxLayout(self.centralwidget)
        self.horizontalLayout.setContentsMargins(20, 20, 20, 20)
        self.graphicsView = QtGui.QGraphicsView(self.centralwidget)
        self.horizontalLayout.addWidget(self.graphicsView)
        ui.setCentralWidget(self.centralwidget)
        self.graphicsView.setGeometry(QtCore.QRect(0, 0, 1000, 300))
        self.graphicscene=QtGui.QGraphicsScene(0,0,1000,300)
        self.graphicsView.setScene(self.graphicscene)
        self.graphicsView.centerOn(0,0)
    def resizeEvent (self, QResizeEvent):
         resize()
 
    def keyPressEvent(self, event):
        if event.key() == QtCore.Qt.Key_Escape:
            self.close()
 
def resize():
    print "im resizing"  # iv tried all sorts here , what am i not seeing ?
 
def draw():
    bru=QtGui.QBrush(QtCore.Qt.SolidPattern)
    bru.setColor(QtGui.QColor(255,000,000))
    pen=QtGui.QPen()
    pen.setColor(QtGui.QColor(255,255,000))
    pen.setWidth(5)
    font=QtGui.QFont('White Rabbit',16)
    dot1=QtGui.QGraphicsTextItem('Graph goes here.\n\nWhat im trying to get is :-\n\nscrolls along X axis with scroll bar, no resizing,\nResizes to fit graphicsView along Y axis.')
    dot1.setFont(font)
    dot1.setPos(5,5)
    ui.graphicscene.addItem(dot1)
    for x in range(10):
        ui.graphicscene.addRect(20+(x*100),200,50,80,pen,bru)
    ui.graphicscene.addRect(0,0,999,300,QtGui.QPen(QtGui.QColor(000,000,255),5,QtCore.Qt.DashLine))
    why=QtGui.QGraphicsTextItem("and why are these gaps here (top and bottom) when first run ?")
    why.setFont(QtGui.QFont('White Rabbit',15))
    why.setPos(400,-30)
    ui.graphicscene.addItem(why)
 
if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    ui = Ui_MainWindow()
    ui.setupUi(ui)
    ui.show()
    draw()
    sys.exit(app.exec_())

#-------------------------------------------------------------------------------
# Name:        module1
# Purpose:
#
# Author:      User
#
# Created:     20/02/2011
# Copyright:   (c) User 2011
# Licence:     <your licence>
#-------------------------------------------------------------------------------
#!/usr/bin/env python
import sys
from PyQt4 import QtCore, QtGui

class Ui_MainWindow(QtGui.QMainWindow):
    def setupUi(self, ui):
        ui.resize(600, 400)
        self.centralwidget = QtGui.QWidget(ui)
        self.horizontalLayout = QtGui.QHBoxLayout(self.centralwidget)
        self.horizontalLayout.setContentsMargins(20, 20, 20, 20)
        self.graphicsView = QtGui.QGraphicsView(self.centralwidget)
        self.horizontalLayout.addWidget(self.graphicsView)
        ui.setCentralWidget(self.centralwidget)
        self.graphicsView.setGeometry(QtCore.QRect(0, 0, 1000, 300))
        self.graphicscene=QtGui.QGraphicsScene(0,0,1000,300)
        self.graphicsView.setScene(self.graphicscene)
        self.graphicsView.centerOn(0,0)
    def resizeEvent (self, QResizeEvent):
         resize()

    def keyPressEvent(self, event):
        if event.key() == QtCore.Qt.Key_Escape:
            self.close()

def resize():
    print "im resizing"  # iv tried all sorts here , what am i not seeing ?

def draw():
    bru=QtGui.QBrush(QtCore.Qt.SolidPattern)
    bru.setColor(QtGui.QColor(255,000,000))
    pen=QtGui.QPen()
    pen.setColor(QtGui.QColor(255,255,000))
    pen.setWidth(5)
    font=QtGui.QFont('White Rabbit',16)
    dot1=QtGui.QGraphicsTextItem('Graph goes here.\n\nWhat im trying to get is :-\n\nscrolls along X axis with scroll bar, no resizing,\nResizes to fit graphicsView along Y axis.')
    dot1.setFont(font)
    dot1.setPos(5,5)
    ui.graphicscene.addItem(dot1)
    for x in range(10):
        ui.graphicscene.addRect(20+(x*100),200,50,80,pen,bru)
    ui.graphicscene.addRect(0,0,999,300,QtGui.QPen(QtGui.QColor(000,000,255),5,QtCore.Qt.DashLine))
    why=QtGui.QGraphicsTextItem("and why are these gaps here (top and bottom) when first run ?")
    why.setFont(QtGui.QFont('White Rabbit',15))
    why.setPos(400,-30)
    ui.graphicscene.addItem(why)

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    ui = Ui_MainWindow()
    ui.setupUi(ui)
    ui.show()
    draw()
    sys.exit(app.exec_())

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When the window is resized I need the scene to remain 1:1 ratio on the X axis, it can be scrolled (this part works fine atm) & i need the Y axis to be resised to always fit in the graphicsView.


Any help is gratefully appreciated.

[JackDinn]

I got it

def resize():
    width=ui.graphicsView.frameRect().width()
    rr=ui.graphicsView.mapToScene(ui.graphicsView.frameRect())
    ui.graphicsView.fitInView(0,0,width,300)
    ui.graphicsView.ensureVisible(rr.boundingRect(),-2,0)

def resize():
    width=ui.graphicsView.frameRect().width()
    rr=ui.graphicsView.mapToScene(ui.graphicsView.frameRect())
    ui.graphicsView.fitInView(0,0,width,300)
    ui.graphicsView.ensureVisible(rr.boundingRect(),-2,0)

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only have to figure out why it wont initiate properly when first run, any ideas ?

[SixDegrees]

If you're asking for the sizes of components in the constructor, that can cause problems. Components don't have a definite size until they're completely constructed. You'll want to do your resizing after the constructor has finished.

QWidget::ensurePolished() may be helpful here, but a separate function called after construction works.

[JackDinn]

hmm i kinda suspected something like that but iv tried calling the resize() at the last possible point (just before the app loop) but that didn't work.

So whats ensurePolished for then, i shall go have a look

thx.