wxPython + Pyglet

PygletWX.py

"""
LICENSE

Copyright (c) 2014, Rachel Powers All rights reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the BSD license: http://opensource.org/licenses/BSD-3-Clause
"""

import wx
from wx import glcanvas
import pyglet

# this line is very important, we're tricking pyglet into thinking there is a context avalible
# but we can't make it work with the shadow window that alows sharing of
# object between contexts
pyglet.options['shadow_window'] = False

# now that that is set we can import gl and get on our way
from pyglet import gl


class PygletGLPanel(wx.Panel):

    '''A simple class for using pyglet OpenGL with wxPython.'''

    def __init__(self, parent, id, pos=wx.DefaultPosition,
                 size=wx.DefaultSize, style=0):
        # Forcing a no full repaint to stop flickering
        style = style | wx.NO_FULL_REPAINT_ON_RESIZE
        self.FIRST_PAINT = False
        # call super function
        super(PygletGLPanel, self).__init__(parent, id, pos, size, style)
        # init gl canvas data
        self.GLinitialized = False
        attribList = (glcanvas.WX_GL_RGBA,  # RGBA
                      glcanvas.WX_GL_DOUBLEBUFFER,  # Double Buffered
                      glcanvas.WX_GL_DEPTH_SIZE, 24)  # 24 bit
        # Create the canvas
        self.sizer = wx.BoxSizer(wx.HORIZONTAL)
        self.canvas = glcanvas.GLCanvas(self, attribList=attribList)
        if wx.VERSION >= (2, 9):
            self.context = glcanvas.GLContext(self.canvas)
        self.sizer.Add(self.canvas, 1, wx.EXPAND)
        self.SetSizer(self.sizer)
        self.Layout()
        # bind events
        self.canvas.Bind(
            wx.EVT_ERASE_BACKGROUND, self.processEraseBackgroundEvent)
        self.canvas.Bind(wx.EVT_SIZE, self.processSizeEvent)
        self.canvas.Bind(wx.EVT_PAINT, self.processPaintEvent)

    #==========================================================================
    # Canvas Proxy Methods
    #==========================================================================

    def GetGLExtents(self):
        '''Get the extents of the OpenGL canvas.'''
        return self.canvas.GetClientSize()

    def SwapBuffers(self):
        '''Swap the OpenGL buffers.'''
        self.canvas.SwapBuffers()

    #==========================================================================
    # wxPython Window Handlers
    #==========================================================================

    def processEraseBackgroundEvent(self, event):
        '''Process the erase background event.'''
        pass  # Do nothing, to avoid flashing on MSWin

    def processSizeEvent(self, event):
        '''Process the resize event.'''

        if wx.VERSION >= (2, 9):
            wx.CallAfter(self.doSetViewport)
        else:
            self.doSetViewport()
        event.Skip()

    def doSetViewport(self):
        if wx.VERSION >= (2, 9):
            self.Show()
            self.PrepareGL()
            # Make sure the frame is shown before calling SetCurrent.
            self.canvas.SetCurrent(self.context)
            size = self.GetGLExtents()
            self.winsize = (size.width, size.height)
            self.width, self.height = size.width, size.height
            if self.width < 0:
                self.width = 1
            if self.height < 0:
                self.height = 1
            self.OnReshape(size.width, size.height)
            self.canvas.Refresh(False)
        else:
            if self.canvas.GetContext():
                # Make sure the frame is shown before calling SetCurrent.
                self.Show()
                self.PrepareGL()
                self.canvas.SetCurrent()
                size = self.GetGLExtents()
                self.winsize = (size.width, size.height)
                self.width, self.height = size.width, size.height
                if self.width < 0:
                    self.width = 1
                if self.height < 0:
                    self.height = 1
                self.OnReshape(size.width, size.height)
                self.canvas.Refresh(False)

    def PrepareGL(self):
        if wx.VERSION >= (2, 9):
            self.canvas.SetCurrent(self.context)
        else:
            self.canvas.SetCurrent()

        # initialize OpenGL only if we need to
        if not self.GLinitialized:
            self.OnInitGL()
            self.GLinitialized = True
            size = self.GetGLExtents()
            self.OnReshape(size.width, size.height)

        self.pygletcontext.set_current()

    def processPaintEvent(self, event):
        '''Process the drawing event.'''
        if not self.FIRST_PAINT:
            self.FIRST_PAINT = True
        self.PrepareGL()
        self.OnDraw()
        event.Skip()

    def Destroy(self):
        # clean up the pyglet OpenGL context
        self.pygletcontext.destroy()
        # call the super metho
        super(wx.Panel, self).Destroy()

    #==========================================================================f
    # GLFrame OpenGL Event Handlers
    #==========================================================================

    def OnInitGL(self):
        '''Initialize OpenGL for use in the window.'''
        # create a pyglet context for this panel
        #self.pygletcontext = gl.Context(gl.current_context)
        if pyglet.version > "1.1.4":
            self.pygletcontext = PygletWXContext()
        else:
            self.pygletcontext = gl.Context()
        self.pygletcontext.set_current()
        # normal gl init
        gl.glEnable(gl.GL_BLEND)
        gl.glBlendFunc(gl.GL_SRC_ALPHA, gl.GL_ONE_MINUS_SRC_ALPHA)
        gl.glEnable(gl.GL_TEXTURE_2D)
        gl.glClearColor(1, 1, 1, 1)

        # create objects to draw
        self.create_objects()

    def OnReshape(self, width, height):
        '''Reshape the OpenGL viewport based on the dimensions of the window.'''
        # CORRECT WIDTH AND HEIGHT
        if width <= 0:
            width = 1
        if height <= 0:
            height = 1
        if self.GLinitialized:
            self.pygletcontext.set_current()
        gl.glViewport(0, 0, width, height)
        gl.glMatrixMode(gl.GL_PROJECTION)
        gl.glLoadIdentity()
        gl.glOrtho(0, width, 0, height, 1, -1)
        gl.glMatrixMode(gl.GL_MODELVIEW)
        if self.GLinitialized:
            self.update_object_resize(width, height)

    def OnDraw(self, *args, **kwargs):
        "Draw the window."
        # clear the context
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)
        # draw objects
        self.draw_objects()
        # update screen
        self.SwapBuffers()

    #==========================================================================
    # To be implemented by a sub class
    #==========================================================================

    def create_objects(self):
        '''create opengl objects when opengl is initialized'''
        pass

    def update_object_resize(self, width, height):
        '''called when the window receives only if opengl is initialized'''
        pass

    def draw_objects(self):
        '''called in the middle of ondraw after the buffer has been cleared'''
        pass


class PygletWXContext(gl.Context):

    def __init__(self, config=None, context_share=None):
        self.config = config
        self.context_share = context_share
        self.canvas = None

        if context_share:
            self.object_space = context_share.object_space
        else:
            self.object_space = gl.ObjectSpace()

    def attach(self, canvas=None):
        pass

    def detach(self):
        pass

    def set_current(self):
        # XXX not per-thread
        gl.current_context = self

        # XXX
        gl.gl_info.set_active_context()
        gl.glu_info.set_active_context()

        # Implement workarounds
        if not self._info:
            self._info = gl.gl_info.GLInfo()
            self._info.set_active_context()
            for attr, check in self._workaround_checks:
                setattr(self, attr, check(self._info))

        # Release textures and buffers on this context scheduled for deletion.
        # Note that the garbage collector may introduce a race condition,
        # so operate on a copy of the textures/buffers and remove the deleted
        # items using list slicing (which is an atomic operation)
        if self.object_space._doomed_textures:
            textures = self.object_space._doomed_textures[:]
            textures = (gl.GLuint * len(textures))(*textures)
            gl.glDeleteTextures(len(textures), textures)
            self.object_space._doomed_textures[0:len(textures)] = []
        if self.object_space._doomed_buffers:
            buffers = self.object_space._doomed_buffers[:]
            buffers = (gl.GLuint * len(buffers))(*buffers)
            gl.glDeleteBuffers(len(buffers), buffers)
            self.object_space._doomed_buffers[0:len(buffers)] = []

#-------------------------------------------------------------------------
# EditorGLPanel
#-------------------------------------------------------------------------


class EditorGLPanel(PygletGLPanel):

    def __init__(self, parent, id=wx.ID_ANY, rows=1, columns=1, coord=(0, 0), drawmode=1):
        """Basic constructor for the wxGLCanvas

        Arguments:
        parent -- The wxWindow instance to set as this panel's parent
        id -- The ID of the panel
        rows -- The number of horizontal rows used for tiles
        columns -- The number of vertical columns used for tiles
        coord -- The coordinate of the tile that the image will draw from the source
        drawmode -- An integer to decide what drawing mode will be used.
            0: CropAndShrink -- Images will be both scaled down and cropped to fit
            1: Shrink -- Scales image down if too large, else the image is simply centered
            2: StretchAspect -- The image will be stretched to fill panel while maintaining aspect ratio
            3: Cropped -- Oversized images too large for the panel will simply be cropped
            4: Stretch -- The entire image is stretched, and aspect ratio is ignored
            5: TopLeft -- Image is anchored to top left corner and cropped
        Returns:
        None

        """
        super(EditorGLPanel, self).__init__(parent, id)
        self._rows = rows
        self._columns = columns
        self._coord = coord
        self._drawmode = drawmode
        self._image = None
        self.draw_objects()
        self._contextMenu = None
        self.canvas.Bind(wx.EVT_RIGHT_DOWN, self.canvas_RightClicked)

    def SetRows(self, rows):
        if rows < 1:
            rows = 1
        self._rows = rows

    def SetColumns(self, columns):
        if columns < 1:
            columns = 1
        self._columns = columns

    def canvas_RightClicked(self, event):
        """Creates the context menu if necessary, then displays it"""
        if self._contextMenu is None:
            self._createContextMenu()
        self._contextMenu.Check(self._drawmode, True)
        self.canvas.PopupMenu(self._contextMenu, event.GetPosition())

    def menuItem_SelectionChanged(self, event):
        """updates the draw mode"""
        self.SetDrawMode(event.GetId())

    def _createContextMenu(self):
        """Creates the context menu on demand"""
        self._contextMenu = wx.Menu()
        self.menuItemCropAndShrink = wx.MenuItem(
            self._contextMenu, 0, "Crop and Shrink", "Oversized images will be scaled and cropped evenly", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemCropAndShrink)
        self.menuItemCropAndShrink.Check(True)
        self.menuItemShrink = wx.MenuItem(
            self._contextMenu, 1, "Shrink", "Oversized images will scale to the windows size while maintaining aspect ratio", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemShrink)
        self.menuItemStretchAspect = wx.MenuItem(
            self._contextMenu, 2, "Stretch Aspect", "Images will expand to fill the window while maintaining aspect ratio", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemStretchAspect)
        self.menuItemCrop = wx.MenuItem(
            self._contextMenu, 3, "Crop", "Image will be cropped to the window's size", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemCrop)
        self.menuItemStretch = wx.MenuItem(
            self._contextMenu, 4, "Stretch", "Image will be stretched to fill the window and ignore the aspect ratio", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemStretch)
        self.menuItemNone = wx.MenuItem(
            self._contextMenu, 5, "None", "No resizing, cropping, or centering will be performed", wx.ITEM_RADIO)
        self._contextMenu.AppendItem(self.menuItemNone)
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemCropAndShrink.GetId())
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemShrink.GetId())
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemStretchAspect.GetId())
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemCrop.GetId())
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemStretch.GetId())
        self.Bind(wx.EVT_MENU, self.menuItem_SelectionChanged,
                  id=self.menuItemNone.GetId())

    def ChangeImage(self, pilImage):
        """Changes the displayed image"""
        self._image = pilImage
        del (pilImage)
        if self.FIRST_PAINT:
            self.PrepareGL()
            self.OnDraw()

    def GetDrawMode(self):
        """Returns the integer value that represents the current drawing mode"""
        return self._drawmode

    def SetDrawMode(self, drawmode):
        """Sets the drawing mode and refreshes the display"""
        self._drawmode = drawmode
        if self.FIRST_PAINT:
            self.PrepareGL()
            self.OnDraw()

    def draw_objects(self):
        """Draws the objects on the canvas"""
        if not self.GLinitialized:
            return

        # clear the screen
        gl.glClearColor(0.93, 0.93, 0.93, 1)
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)

        if self._image is None:
            return
        # Convert PIL image to pyglet image
        srcImage = pyglet.image.create(*self._image.size).get_image_data()
        pitch = -len('RGBA') * srcImage.width
        data = self._image.tostring()
        srcImage.set_data('RGBA', pitch, data)
        # Clear the canvas and calculate the region to draw
        tile_width = srcImage.width // self._rows
        tile_height = srcImage.height // self._columns
        x = self._coord[0] * tile_width
        y = self._coord[1] * tile_height
        y = srcImage.height - y - tile_height
        subimage = srcImage.get_region(x, y, tile_width, tile_height)
        subimage.align_x = subimage.align_y = 0
        # Branch by what mode is selected to draw
        if self._drawmode == 0:
            self.CropAndShrink(subimage)
        elif self._drawmode == 1:
            self.Shrink(subimage)
        elif self._drawmode == 2:
            self.StretchAspect(subimage)
        elif self._drawmode == 3:
            self.Cropped(subimage)
        elif self._drawmode == 4:
            self.Stretch(subimage)
        else:
            self.TopLeft(subimage)
        del (srcImage)

    #---------------------------------------------------------------
    # Draw Modes
    #---------------------------------------------------------------
    def CropAndShrink(self, pygletimage):
        """Images will be both scaled down and cropped to fit"""
        width, height = self.GetClientSize()
        w, h = pygletimage.width, pygletimage.height
        x, y, = (width - w) // 2, (height - h) // 2
        if width < w or height < h:
            diff_w = (w - width) // 2
            diff_h = (h - height) // 2
            pygletimage.blit(x // 2, y // 2, 0, w - diff_w, h - diff_h)
        else:
            pygletimage.blit(x, y, 0, w, h)
        del (pygletimage)

    def Shrink(self, pygletimage):
        """Scales image down if too large, else the image is simply centered"""
        width, height = self.GetClientSize()
        w, h = pygletimage.width, pygletimage.height
        x, y, = (width - w) // 2, (height - h) // 2
        if width < w or height < h:
            self.StretchAspect(pygletimage)
        else:
            pygletimage.blit(x, y, 0, w, h)
        del (pygletimage)

    def StretchAspect(self, pygletimage):
        """The image will be stretched to fill panel while maintaining aspect ratio"""
        width, height = self.GetClientSize()
        w, h = pygletimage.width, pygletimage.height
        x_ratio = float(width) / w
        y_ratio = float(height) / h
        if y_ratio > x_ratio:
            ch = h * x_ratio
            pygletimage.blit(0, (height - ch) // 2, 0, width, ch)
        else:
            cw = w * y_ratio
            pygletimage.blit((width - cw) // 2, 0, 0, cw, height)
        del (pygletimage)

    def Cropped(self, pygletimage):
        """Oversized images too large for the panel will simply be cropped"""
        width, height = self.GetClientSize()
        w, h = pygletimage.width, pygletimage.height
        x, y = (width - w) // 2, (height - h) // 2
        if w > width:
            x = (width - w) // 2
        if h > height:
            y = (height - h) // 2
        pygletimage.blit(x, y, 0, w, h)
        del (pygletimage)

    def Stretch(self, pygletimage):
        """The entire image is stretched, and aspect ratio is ignored"""
        width, height = self.GetClientSize()
        pygletimage.blit(0, 0, 0, width, height)

    def TopLeft(self, pygletimage):
        """Image is anchored to top left corner and cropped"""
        y = self.GetClientSize()[1] - pygletimage.height
        pygletimage.blit(0, y, 0, pygletimage.width, pygletimage.height)
        del (pygletimage)

Thanks for writing this @Ryex! Any chance you could add a licence to it (ideally a permissive one)? I'd like to incorporate it into my project, but I can't do so if it's unlicensed.

@alexdewar This code was developed as part of my work on ARC many years ago. ARC is BSD licensed so as far as I'm concerned this code is too. I'll add it to the top of the file.

Thank you! 😄