tkImg / Bugs / #79 Grayscale PNG renders incorrectly

Img is a collection of format handlers for the Tk photo image type.

#79 Grayscale PNG renders incorrectly

Milestone: 1.4.0

Status: closed

Owner: Paul Obermeier

Labels: None

Priority: 3

Updated: 2015-06-23

Created: 2014-04-10

Creator: David Nagle

Private: No

It appears that tkimg no longer properly supports grayscale pngs. This image worked up through SVN revision 360:

image create photo camera -format png -data {
    iVBORw0KGgoAAAANSUhEUgAAAA8AAAAPCAQAAACR313BAAAAqElEQVR4AX2JsQnCYBQGj4QI
    tlbZQQfIBEI6BUFLBxCyQiprY+0CzmARzAIqEdIFxDbgACmer/h5EKN+xwcHh81nxhqFBQG9
    nRDjio9bwJKUHdLhQMqKAdyQn9xBjIaMjb5BDJMLIUOm+lC9l8fEvBB9rP6RayB3ngN1N5dA
    5bwCym5uGZE4T9Rby44jHhFbvaculo2CORN9gRg8TPs8PSIyzl/ZE/F/b0pal5I9AYRrAAAA
    AElFTkSuQmCC
}

Starting in revision 361 (and still present in the current revision 368), the image appears to load without complaint. But instead of rendering as a camera, it instead renders as a solid black box.

If I re-encode the images in sRGB, it works. For instance, this is the same image encoded in sRGB and it renders properly:

image create photo camera -format png -data {
    iVBORw0KGgoAAAANSUhEUgAAAA8AAAAPCAMAAAAMCGV4AAAABGdBTUEAALGPC/xhBQAAAAFz
    UkdCAK7OHOkAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAA
    AI1QTFRFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
    AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
    AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA////6jkV6gAAAC10Uk5TAANQ
    YFQFu9BXgJCcWAbR1OyRbM8YCUYrSe/ev9PX+xJvqQI4hsJRLOHjGcAb6AEv2AAAAAFiS0dE
    LlTTEIcAAAB/SURBVAjXXY7XAoIwEAQXI0qxEAHpXcDC/f/vEQIBdR72bh6uAAJtxxjb61Ac
    aOKoTb1umBbN2ObpjAt9c4UsDr9xR3bSXc+/+567ehBGFIWB8hiJyATx4ikykRnSxfOiFFkW
    uZqv6ubR1NW6j9qu79r53vPnnxfe1meDD/hjBNZcGzQhwcVZAAAAJXRFWHRkYXRlOmNyZWF0
    ZQAyMDE0LTA0LTEwVDE3OjAwOjAxLTA0OjAwVyaSvgAAACV0RVh0ZGF0ZTptb2RpZnkAMjAx
    NC0wNC0xMFQxNzowMDowMS0wNDowMCZ7KgIAAAAASUVORK5CYII=
}

I am using Tcl/Tk 8.6.1. I have tested this on two separate Linux systems.

Discussion

Jan Nijtmans - 2014-11-07

Group: 1.2.4 --> 1.4.0
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Jan Nijtmans - 2014-11-07

Confirmed. I indeed can reproduce this. Paul, any idea?

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Jan Nijtmans - 2014-11-07

assigned_to: Paul Obermeier

Priority: 1 --> 3
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Paul Obermeier - 2014-12-27

Fixed with revision 370.

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Jan Nijtmans - 2015-06-23

Fixed by Paul

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Jan Nijtmans - 2015-06-23

status: open --> closed
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Grayscale PNG renders incorrectly

Img is a collection of format handlers for the Tk photo image type.

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#79 Grayscale PNG renders incorrectly

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