[PyObjC CoreGraphics API Example] Shows how to use the functional API of the CoreGraphics framework through PyObjC and Python 2.7. #pyobjc #python #coregraphics #quartz #macos #examples

pyobjc_coregraphics_example1.py

#!/usr/local/bin/python
# -*- coding: utf-8 -*-
# 
#  pyobjc_coregraphics_example1.py
#  PyObjC Scripts
#  
#  Created by André Berg on 2013-07-09.
#  Copyright 2013 Berg Media. All rights reserved.
# 
#  Example script that shows how to use 
#  the functional API of the CoreGraphics
#  framework through PyObjC and Python 2.7
#

import math
import os
import operator
from subprocess import Popen, PIPE

import Quartz
from Quartz.CoreGraphics import *
from Cocoa import *


WIDTH = 256
HEIGHT = 256
BITDEPTH = 8

# Doesn't seem like these are translated and defined by the PyObjC bridge 
# somewhere, so define them here. For reference, see:
# http://developer.apple.com/library/ios/#documentation/graphicsimaging/conceptual/ImageIOGuide/imageio_basics/ikpg_basics.html
kUTTypeImage = "public.image"
kUTTypePNG = "public.png"
kUTTypeJPEG = "public.jpeg"
kUTTypeJPEG2000 = "public.jpeg-2000"
kUTTypeTIFF = "public.tiff"
kUTTypePICT = "com.apple.pict"
kUTTypeGIF = "com.compuserve.gif"


def MakeImage(width, height, bitdepth):
    
    c = CGBitmapContextCreate(None, width, height, BITDEPTH, width * 4, CGColorSpaceCreateDeviceRGB(), 1)
    
    CGContextSetRGBStrokeColor(c, 1, 0, 0, 1)
    CGContextSetRGBFillColor(c, 1, 1, 0, 0.5)
    CGContextSetLineJoin(c, kCGLineJoinBevel)
    
    CGContextSetLineWidth(c, 8)
    x0   = (32.5, 32.5)
    size = (191, 191)
    rect = CGRect(x0, size)
    CGContextAddRect(c, rect)
    
    CGContextSetLineWidth(c, 6)
    CGContextMoveToPoint(c, *x0)
    x1 = map(operator.add, x0, size)
    CGContextAddLineToPoint(c, *x1)
    
    CGContextDrawPath(c, kCGPathFillStroke)
    
    CGContextTranslateCTM(c, 128, 128)
    CGContextRotateCTM(c, math.radians(90))
    CGContextTranslateCTM(c, -128, -128)
    
    CGContextSetRGBStrokeColor(c, 0, 0, 0, 1)
    CGContextSetRGBFillColor(c, 1, 1, 1, 0.8)
    CGContextSelectFont(c, "Helvetica", 36, kCGEncodingMacRoman)
    CGContextSetTextPosition(c, 32, 118)
    CGContextSetTextDrawingMode(c, kCGTextFillStroke)
    CGContextSetShadow(c, NSMakePoint(0, -10), 20)
    CGContextShowText(c, "Hello world!", 3)
    
    cgimg = CGBitmapContextCreateImage(c)
    nsimg = NSImage.alloc().initWithCGImage_size_(cgimg, NSMakeSize(width, height))
    
    #CFRelease(cgimg)
    #nsimg.release()
    
    return nsimg

  
def CGWriteToFile(image, path, format):
    url = NSURL.fileURLWithPath_(path)
    destination = CGImageDestinationCreateWithURL(url, format, 1, None)
    CGImageDestinationAddImage(destination, image, None)
    
    if not CGImageDestinationFinalize(destination):
        NSLog("Failed to write image to %s", path)
    
    #CFRelease(destination)


def NSImageWriteToFile(image, path, format):
    ''' Write image representation as data to an image file. 
    
    ``format`` can be one of the file type constants, i.e. ``NSPNGFileType``.
    '''
    imgRep = image.representations().objectAtIndex_(0)
    
    image.lockFocus()
    rect = NSMakeRect(0.0, 0.0, image.size().width, image.size().height)
    imgRep = NSBitmapImageRep.alloc().initWithFocusedViewRect_(rect)
    image.unlockFocus()
    
    data = imgRep.representationUsingType_properties_(format, None)
    data.writeToFile_atomically_(path, False)
    
    #CFRelease(imgRep)


def system(cmd, args=None):
    '''
    Convenience function for firing off commands to 
    the system console. Used instead of `subprocess.call`_
    so that shell variables will be expanded properly.
    
    Not the same as `os.system`_ as here it captures 
    returns ``stdout`` and ``stderr`` in a tuple in
    Python 2.5 and lower or a ``namedtuple`` in 2.6
    and higher. So you can use ``result[0]`` in the
    first case and ``result.out`` in the second.

    :param cmd: a console command line
    :type cmd: ``string``
    :param args: a list of arguments that 
                 will be expanded in cmd 
                 starting with ``$0``
    :type args: ``list``
    :return: ``tuple`` or ``namedtuple``
    '''
    if args is None:
        fullcmd = cmd
    else:
        args = ["'{}'".format(s.replace(r'\\', r'\\\\')
                               .replace("'", r"\'")) for s in args]
        fullcmd = "%s %s" % (cmd, ' '.join(args))
    out, err = Popen(fullcmd, stdout=PIPE, shell=True).communicate()
    system.out = out
    system.err = err
    try:
        from collections import namedtuple
        StdStreams = namedtuple('StdStreams', ['out', 'err'])
        return StdStreams(out=out, err=err)
    except ImportError:
        return (out, err)


if __name__ == '__main__':
    image = MakeImage(WIDTH, HEIGHT, BITDEPTH)

    NSImageWriteToFile(image, 'out.jpg', NSJPEGFileType)
    NSImageWriteToFile(image, 'out.png', NSPNGFileType)
    NSImageWriteToFile(image, 'out.tiff', NSTIFFFileType)
    
    system('open', args=[os.path.realpath('out.tiff')])