代码之家 › 专栏 › 技术社区 › Clinton Blackmore

在pyobjc中的nsImage上绘制文本时出错

ruby-cocoa pyobjc annotations image cocoa

1

Clinton Blackmore · 技术社区 · 17 年前

我试着用pyobjc在图像上覆盖一些文本,同时努力回答我的问题, "Annotate images using tools built into OS X" . 通过引用 CocoaMagic ,用Rubyobjc替代 RMagick ,我想到了:

#!/usr/bin/env python

from AppKit import *

source_image = "/Library/Desktop Pictures/Nature/Aurora.jpg"
final_image = "/Library/Desktop Pictures/.loginwindow.jpg"
font_name = "Arial"
font_size = 76
message = "My Message Here"

app = NSApplication.sharedApplication()  # remove some warnings

# read in an image
image = NSImage.alloc().initWithContentsOfFile_(source_image)
image.lockFocus()

# prepare some text attributes
text_attributes = NSMutableDictionary.alloc().init()
font = NSFont.fontWithName_size_(font_name, font_size)
text_attributes.setObject_forKey_(font, NSFontAttributeName)
text_attributes.setObject_forKey_(NSColor.blackColor, NSForegroundColorAttributeName)

# output our message
message_string = NSString.stringWithString_(message)
size = message_string.sizeWithAttributes_(text_attributes)
point = NSMakePoint(400, 400)
message_string.drawAtPoint_withAttributes_(point, text_attributes)

# write the file
image.unlockFocus()
bits = NSBitmapImageRep.alloc().initWithData_(image.TIFFRepresentation)
data = bits.representationUsingType_properties_(NSJPGFileType, nil)
data.writeToFile_atomically_(final_image, false)

当我运行它时,我得到:

Traceback (most recent call last):
  File "/Users/clinton/Work/Problems/TellAtAGlance/ObviouslyTouched.py", line 24, in <module>
    message_string.drawAtPoint_withAttributes_(point, text_attributes)
ValueError: NSInvalidArgumentException - Class OC_PythonObject: no such selector: set

在文档中查找drawatpoint:withattributes:,它说,“只有当nsview有焦点时才应该调用这个方法。”nsImage不是nsview的子类,但我希望它可以工作,而且在ruby示例中,类似的东西似乎可以工作。

我需要做什么改变才能使这个工作成功?

我重写了代码,忠实地将它转换为Objy-C基础工具。它工作,没有问题。[如果有理由,我很乐意在这里发布。]

问题就变成了,如何做到:

[message_string drawAtPoint:point withAttributes:text_attributes];

不同于

message_string.drawAtPoint_withAttributes_(point, text_attributes)

?有没有一种方法来判断哪个“oc-pythonobject”引发了nsinvalidargumentexception?

1 回复 | 直到 17 年前

1

Clinton Blackmore 17 年前

上述代码中存在以下问题:

text_attributes.setObject_forKey_(NSColor.blackColor, NSForegroundColorAttributeName)
->
text_attributes.setObject_forKey_(NSColor.blackColor(), NSForegroundColorAttributeName)

bits = NSBitmapImageRep.alloc().initWithData_(image.TIFFRepresentation)
data = bits.representationUsingType_properties_(NSJPGFileType, nil)
->
bits = NSBitmapImageRep.imageRepWithData_(image.TIFFRepresentation())
data = bits.representationUsingType_properties_(NSJPEGFileType, None)

确实有一些小错误。

请注意,代码的中间部分可以用更可读的变体替换:

# prepare some text attributes
text_attributes = { 
    NSFontAttributeName : NSFont.fontWithName_size_(font_name, font_size),
    NSForegroundColorAttributeName : NSColor.blackColor() 
}

# output our message 
NSString.drawAtPoint_withAttributes_(message, (400, 400), text_attributes)

我通过查看源代码 NodeBox 十二行 psyphography.py 和 cocoa.py 尤其是save和getImageData方法。