BlitTest.py

#!/usr/bin/env python

"""
demo oif blitting from a MemoryDC to the screen using DC.DrawBitmap
"""

from __future__ import print_function, unicode_literals

import random
import wx


class MainWindow(wx.Frame):
    """ This window displays some random lines """

    def __init__(self, parent, id, title):
        wx.Frame.__init__(
            self,
            None,
            -1,
            "Blit Test",
            wx.DefaultPosition,
            size=(500, 500),
            style=wx.DEFAULT_FRAME_STYLE | wx.NO_FULL_REPAINT_ON_RESIZE)

        wx.EVT_CLOSE(self, self.OnQuit)
        self.Bind(wx.EVT_TIMER, self.OnTimer)
        self.Bind(wx.EVT_SIZE, self.BuildImage)

        self.Numtimer = 0
        self.NumLines = 100

        self.t = wx.Timer(self)
        self.BuildImage()
        self.t.Start(100)

    def OnQuit(self, Event):
        self.Destroy()

    def BuildImage(self, event=None):
        Size = self.ClientSize

        # Make new offscreen bitmap: this bitmap will always have the
        # current drawing in it, so it can be used to save the image to
        # a file, or whatever.
        print("making new buffer:", Size)
        self._Buffer = wx.EmptyBitmap(Size[0], Size[1])

        dc = wx.MemoryDC()
        dc.SelectObject(self._Buffer)

        self.Lines = []
        for i in range(self.NumLines):
            x1, y1, x2, y2 = (random.randint(1, max(Size)),
                              random.randint(1, max(Size)),
                              random.randint(1, max(Size)),
                              random.randint(1, max(Size)))

            color = self.random_color()
            self.Lines.append([color, (x1, y1, x2, y2)])

        dc.Clear()
        for line in self.Lines:
            dc.SetPen(wx.Pen(line[0], 2))
            dc.DrawLine(*line[1])

    def OnTimer(self, event):
        self.Numtimer += 1
        print("Timer fired: %i times" % self.Numtimer)

        # change one color:
        self.Lines[random.randrange(self.NumLines)][0] = self.random_color()
        # update the screen
        dc = wx.MemoryDC()
        dc.SelectObject(self._Buffer)
        dc.Clear()
        for line in self.Lines:
            dc.SetPen(wx.Pen(line[0], 2))
            dc.DrawLine(*line[1])
        # del dc
        wx.ClientDC(self).DrawBitmap(self._Buffer, 0, 0)

    def random_color(self):
        return wx.Colour(random.randrange(255),
                         random.randrange(255),
                         random.randrange(255),
                         )


class MyApp(wx.App):
    def OnInit(self):

        frame = MainWindow(None, wx.ID_ANY, title="BlitTest")
        self.SetTopWindow(frame)
        frame.Show()

        return True


app = MyApp(0)
app.MainLoop()