ico file format

7/27/2019 Ico File Format

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ESCUELA POLITECNICA DEL EJERCITO

Danilo Neto


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ICO FILE FORMAT

The first icons were developed in the 1970s by Xerox PARC David Canfield

SmithThe ICO file format is an image file format for computer icons inMicrosoft Windows.

In Windows, all executables that display an icon to the user, on the desktop,in the Start Menu, or in Windows Explorer, must carry the icon in ICO format.

ICO files contain one or more small images at multiple sizes and color depths ,

such that they may be scaled appropriately.


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ICO FILE FORMAT

Icons introduced in Windows 1.0 were 3232 pixels in size and weremonochrome.

Support for 16 colours was introduced in Windows 3.0

Win32 introduced support for storing icon images of up to 16.7 million colors(Truecolor) and up to 256x256 pixels in dimensions.

Windows 95 introduced 24-bit RGB colorspace and several larger dimensions

()64x64, 128x128, It was possible to enable 65535 color (Highcolor) icons byeither modifying the Shell Icon BPP value in the registry.

Windows XP, by default, employs 4848 pixel icons in Windows Explorer

Windows Vista adds support for displaying 256256 pixel icon images as aseparate view in Windows Explorer. The Windows Vista shell adds a slider for"zooming" the icon sizes in and out.


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ICO FILE FORMAT An ICO or CUR file is made up of an

ICONDIR ("Icon directory") structure,containing an ICONDIRENTRY structure for

each image in the file, followed by acontiguous block of all image bitmap data.

ICONDIR structure

Offset#Size (in

bytes)Purpose

0 2 Reserved. Must always be 0.

2 2

Specifies image type: 1 for

icon (.ICO) image, 2 for

cursor (.CUR) image. Other

values are invalid.

4 2

Specifies number of images

in the file.

ICONDIRENTRY structure

Offset# Size (in bytes) P

0 1Specifies image width number between 0 and

width is 256 pixels.

1 1

Specifies image height

number between 0 andheight is 256 pixels.

2 1

Specifies number of co

Should be 0 if the imag

palette.

3 1 Reserved. Should be 0

4 2

In ICO format: Specifie

or 1.[Notes 3]In CUR form

coordinates of the hot

from the left.

6 2

In ICO format: Specifie

CUR format: Specifies

the hotspot in number

8 4 Specifies the size of th

12 4Specifies the offset of

beginning of the ICO/C
http://en.wikipedia.org/wiki/ICO_(file_format)http://en.wikipedia.org/wiki/Offset_(computer_science)http://en.wikipedia.org/wiki/Offset_(computer_science)http://en.wikipedia.org/wiki/ICO_(file_format)

ico file format

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