img-png(3tk)

💖 img-png — the manual page, but make it cute 💖

okay bestie, this is img-png(3tk) from the Img manual family — yes, that Img, the Tcl/Tk image situation. grab a strawberry 🍓 and let's get into it.

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✨ NAME ✨

img-png — Portable Network Graphics format (png). that's it. that's the name. iconic behavior honestly 🎀

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🌸 SYNOPSIS 🌸

package require img::png ?2.1?

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💅 DESCRIPTION 💅

so first things first:

package require img::png

Like every package in Img, this one does not hand you brand-new commands. nope. it extends the Tk command image you already know and love, so that image can handle files containing raster images in the Portable Network Graphics format (png). more specifically? img::png extends Tk's photo image type — the docs for that live at https://www.tcl.tk/man/tcl9.0/TkCmd/photo.html if you wanna peek 👀

The name of the new format handler is png. This handler provides new additional configuration options. See section Options for more detailed explanations. iykyk ✨

All of the above means that in a call like:

image create photo ?name? ?options?

1. Image data in png format (options -data and -file) is detected automatically. no cap, it just knows 🦋
2. The format name png is recognized by the option -format.

In addition the value of option -format is treated as a list and may contain any of the special options listed in section Options. it's giving multitasking 💅

The package img::png is a sub-package of Img. It can be loaded as a part of the complete Img support, via package require Img, or on its own, via package require img::png. your choice, main character 🫶

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📝 NOTES 📝

1. Chapter Image Metadata of the Img manual page describes the parameters of the resolution related options. (yes bestie, that's where the resolution lore lives 📖)

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🔥 OPTIONS 🔥

The handler provides the following options:

• -verbose bool — This option is supported for reading and writing. Available since version 1.4.6. If set to true, additional information about the read or written image is printed to stdout. Default is false. so like, it spills the tea to your terminal ✨
• -alpha double — This option is supported for reading only. Available since version 1.4.2. An additional alpha filtering value for the overall image, which allows the background on which the image is displayed to show through. This usually also has the effect of desaturating the image. The alpha value must be between 0.0 and 1.0. Specifying an alpha value overrides the setting of the -withalpha flag, i.e. reading a file which has no alpha channel (Grayscale, RGB) will add an alpha channel to the image independent of the -withalpha flag setting. dramatic? maybe. true? yes 💀
• -gamma double — This option is supported for reading only. Available since version 1.4.6. Use the specified gamma value when reading an image. This option overwrites gamma values specified in the file. If this option is not specified and no gamma value is in the file, a default value of 1.0 is used. it said "my gamma now" 😭
• -withalpha bool — This option is supported for reading and writing. Available since version 1.4.1. If set to false, an alpha channel is ignored during reading or writing. Default is true.

Note: This option was named -matte in previous versions and is still recognized. glow-up era 💅

• -resolution xres ?yres? — This option is supported for writing only. Available since version 2.0. Set the resolution values of the written image file. If yres is not specified, it is set to the value of xres. If option is not specified, the DPI and aspect values of the metadata dictionary are written. If no metadata values are available, no resolution values are written. no metadata, no resolution, we simply move on 🧚
• -xresolution xres — This option is supported for writing only. Available since version 2.0. Set the horizontal resolution value of the written image file. horizontal baddie 🎀
• -yresolution yres — This option is supported for writing only. Available since version 2.0. Set the vertical resolution value of the written image file. vertical baddie 🎀
• -tag key value — This option is supported for writing only. Available since version 2.0. Each key-value pair will be written as a named text chunk where the key provides the name of the chunk and the value its contents. Currently the maximum number of -tag specifications are 10. ten. that's the limit bestie, don't push it 🙈

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👑 SEE ALSO 👑

img, img-bmp, img-dted, img-flir, img-gif, img-ico, img-jpeg, img-pcx, img-pixmap, img-png, img-ppm, img-ps, img-raw, img-sgi, img-sun, img-tga, img-tiff, img-window, img-xbm, img-xpm

the whole squad, together, as it should be 🌈

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💜 COPYRIGHT 💜

Copyright (c) 1995-2025 Jan Nijtmans <nijtmans@users.sourceforge.net>
Copyright (c) 2002-2025 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Copyright (c) 2003-2025 Paul Obermeier <obermeier@users.sourceforge.net>

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and that's the whole page, bestie 🫶 this was img-png, version 2.1, hanging out in section 3tk — thanks for reading, you absolutely ate 💅✨💖