wx.EmptyImage() give me black image, but I need white image

wxPython Users
1

I use wx.EmptyImage() to create a empty image, but this image is black.
How to create white image or change black to while.

Thanks

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jiang zhixiang

2

You could try:
    NameOfImage.Replace(0,0,0,255,255,255)

Gadget/Steve

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On 11/09/2012 5:14 AM, Rill wrote:

I use wx.EmptyImage() to create a empty image, but this image is black.
How to create white image or change black to while.

Thanks

3

so good
NameOfImage.Replace(0,0,0,255,255,255) can change balck to white.

Compare image quality, found wx.image is better then PIL

Thanks

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2012/9/11 Gadget/Steve <GadgetSteve@live.co.uk>:

On 11/09/2012 5:14 AM, Rill wrote:

I use wx.EmptyImage() to create a empty image, but this image is black.
How to create white image or change black to while.

Thanks

You could try:
    NameOfImage.Replace(0,0,0,255,255,255)

Gadget/Steve

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jiang zhixiang

4

I wonder if wx guarantees that an EmptyImage will be all black? From the docs:

wxImage(int width, int height, bool clear=true)

Creates an image with the given width and height. If clear is true,
the new image will be initialized to black. Otherwise, the image data
will be uninitialized.

so "clear" needs to be set to True, which is the default in the Python Bindings

But for the record, other options include:

1) create a wx.MemoryDC, set teh backgroundcolor, call Clear(), and
then make an IMage form teh Bitmap.

2) use wxImage.SetData -- passing in, for instance, an array,array of
the right size, maybe something like:

import wx
import array

w, h = 3, 5

img = wx.EmptyImage(w, h, clear = False) # False to show that this works...

arr = array.array('B', (255,)) * (w * h * 3)

img.Data = arr

OK -- that is a lot more work that wx.Image.Replace().

Thanks for bringing that up!

-Chris

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On Mon, Sep 10, 2012 at 11:45 PM, Rill <luckrill@gmail.com> wrote:

so good
NameOfImage.Replace(0,0,0,255,255,255) can change balck to white.

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Christopher Barker, Ph.D.
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Chris.Barker@noaa.gov

5

Rill wrote:

so good
NameOfImage.Replace(0,0,0,255,255,255) can change balck to white.

Compare image quality, found wx.image is better then PIL

It is misleading to make blanket statements like that. PIL is a huge
and enormously capable library that does vastly more than wx.Image.
Most image manipulations will be different. When you save a compressed
image, PIL allows you to specify a quality. If you didn't specify a
quality, then you can't blame the library for choosing higher compression.

Where, exactly, did you see an image quality difference?

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Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.