NAME
bitmap - Define a new bitmap from a Tcl script

SYNOPSIS
bitmap define bitmapName data ?option value?...

bitmap compose bitmapName text ?option value?...

bitmap exists bitmapName

bitmap source bitmapName

bitmap data bitmapName

bitmap height bitmapName

bitmap width bitmapName

DESCRIPTION
The bitmap command lets you define new bitmaps. The bitmap can be specified as a list of data or a text string which is converted into a bitmap. You can arbitrarily scale or rotate the bitmap too.

INTRODUCTION
Bitmaps are commonly used within Tk. In labels and buttons, you can use their pictorial representations instead of text strings. In the canvas and text widgets, they are used for stippling. But if you want to define your own bitmap (i.e. one other than the handful of built-in bitmaps), you must create an ASCII file and let Tk read the bitmap file. This makes it cumbersome to manage bitmaps, especially when you are distributing the program as a wish script, since each bitmap must be its own file. It would be much easier to be able define new bitmaps from Tcl.

The bitmap command lets you do just that. You can define new bitmaps right from a Tcl script. You can specify the bitmap as a list of data, similar to the X11 bitmap format. You can also use bitmap to generate a bitmap from a text string and rotate or scale it as you wish. For example, you could use this to create buttons with the text label rotated ninty degrees.

EXAMPLE
You can define a new bitmap with the define operation. Here is an example that creates a new stipple by defining a new bitmap called "light_gray". bitmap define light_gray { { 4 2 } { 0x08, 0x02 } } Tk will recognize "light_gray" as a bitmap which can now be used with widgets. The last argument is the data which defines the bitmap. It is itself a list of two lists. The first list contains the height and width of the bitmap. The second list is the source data. Each element of the source data is an hexadecimal number specifying which pixels are foreground and which are background of the bitmap. The format of the source data is exactly that of the X11 bitmap format. The define operation is quite lienient about the format of the source data. The data elements may or may not be separated by commas. They may or may not be prefixed by "0x". All of the following definitions are equivalent. bitmap define light_gray { { 4 2 } { 0x08, 0x02 } } bitmap define light_gray { { 4 2 } { 0x08 0x02 } } bitmap define light_gray { { 4 2 } { 8 2 } } You can scale or rotate the bitmap as you create it, by using the -scale or-rotate options. bitmap define light_gray { { 4 2 } { 0x08, 0x02 } } \
    -scale 2.0 -rotate 90.0 You can generate bitmaps from text strings using the compose operation. This makes it easy to create rotated buttons or labels. The text string can have embedded newlines. bitmap compose rot_text "This is rotated\ntext" \
    -rotate 90.0 -font fixed There are a number of ways to query bitmaps. bitmap exists rot_text bitmap width rot_text bitmap height rot_text bitmap data rot_text bitmap source rot_text The exists operation indicates if a bitmap by that name is defined. You can query the dimensions of the bitmap using the width and height operations. The data operation returns the list of the data used to create the bitmap. You can query the data of any bitmap, not just those created by bitmap. This means you can send bitmaps from one application to another. set data [bitmap data @/usr/X11R6/include/X11/bitmaps/ghost.xbm] send {wish #2} bitmap define ghost $data

OPERATIONS
The following operations are available for bitmap:

bitmap compose bitmapName text ?option value?...
    Creates a bitmap bitmapName from the text string text. A bitmap bitmapName can not already exist. The following options are available.

    -font fontName
        Specifies a font to use when drawing text into the bitmap. If this option isn't specified then fontName defaults to *-Helvetica-Bold-R-Normal-*-140-*.

    -rotate theta
        Specifies the angle of rotation of the text in the bitmap. Theta is a real number representing the angle in degrees. It defaults to 0.0 degrees.

    -scale value
        Specifies the scale of the bitmap. Value is a real number representing the scale. A scale of 1.0 indicates no scaling is necessary, while 2.0 would double the size of the bitmap. There is no way to specify differents scales for the width and height of the bitmap. The default scale is 1.0.

bitmap data bitmapName
    Returns a list of both the dimensions of the bitmap bitmapName and its source data.

bitmap define bitmapName data ?option value?...
    Associates bitmapName with in-memory bitmap data so that bitmapName can be used in later calls to Tk_GetBitmap. The bitmapName argument is the name of the bitmap; it must not previously have been defined in either a call to Tk_DefineBitmap or bitmap. The argument data describes the bitmap to be created. It is a list of two elements, the dimensions and source data. The dimensions are a list of two numbers which are the width and height of the bitmap. The source data is a list of hexadecimal values in a format similar to the X11 or X10 bitmap format. The values may be optionally separated by commas and do not need to be prefixed with "0x". The following options are available.

    -rotate theta
        Specifies how many degrees to rotate the bitmap. Theta is a real number representing the angle. The default is 0.0 degrees.

    -scale value
        Specifies how to scale the bitmap. Value is a real number representing the scale. A scale of 1.0 indicates no scaling is necessary, while 2.0 would double the size of the bitmap. There is no way to specify differents scales for the width and height of the bitmap. The default scale is 1.0.

bitmap exists bitmapName
    Returns 1 if a bitmap bitmapName exists, otherwise 0.

bitmap height bitmapName
    Returns the height in pixels of the bitmap bitmapName.

bitmap source bitmapName
    Returns the source data of the bitmap bitmapName. The source data is a list of the hexadecimal values.

bitmap width bitmapName
    Returns the width in pixels of the bitmap bitmapName.

LIMITATIONS
Tk currently offers no way of destroying bitmaps. Once a bitmap is created, it exists until the application terminates.

KEYWORDS
bitmap