bitmap(BLT 2.4) bitmap(BLT 2.4)
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bitmap - Define a new bitmap from a Tcl script
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
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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.
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.
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
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 bitmap-
Name 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.
Tk currently offers no way of destroying bitmaps. Once a bitmap is
created, it exists until the application terminates.
bitmap
bitmap(BLT 2.4)
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