GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
RedHat 5.2(Apollo) |
|
 |
Tk_GetBitmap(3) |
 |
______________________________________________________________________________
Tk_GetBitmap, Tk_DefineBitmap, Tk_NameOfBitmap, Tk_SizeOfBitmap, Tk_FreeBitmap, Tk_GetBitmapFromData − maintain database of single-plane pixmaps
#include <tk.h>
Pixmap
Tk_GetBitmap(interp, tkwin, id)
int
Tk_DefineBitmap(interp, nameId, source, width,
height)
Tk_Uid
Tk_NameOfBitmap(display, bitmap)
Tk_SizeOfBitmap(display, bitmap, widthPtr, heightPtr)
Tk_FreeBitmap(display, bitmap)
|
Tcl_Interp *interp (in) |
Interpreter to use for error reporting. | ||
|
Tk_Window tkwin (in) |
Token for window in which the bitmap will be used. | ||
|
Tk_Uid id (in) |
Description of bitmap; see below for possible values. | ||
|
Tk_Uid nameId (in) |
Name for new bitmap to be defined. | ||
|
char *source (in) |
Data for bitmap, in standard bitmap format. Must be stored in static memory whose value will never change. | ||
|
int width (in) |
Width of bitmap. | ||
|
int height (in) |
Height of bitmap. | ||
|
int *widthPtr (out) |
Pointer to word to fill in with bitmap’s width. | ||
|
int *heightPtr (out) |
Pointer to word to fill in with bitmap’s height. | ||
|
Display *display (in) |
Display for which bitmap was allocated. | ||
|
Pixmap bitmap (in) |
Identifier for a bitmap allocated by Tk_GetBitmap. |
_________________________________________________________________
These procedures manage a collection of bitmaps (one-plane pixmaps) being used by an application. The procedures allow bitmaps to be re-used efficiently, thereby avoiding server overhead, and also allow bitmaps to be named with character strings.
Tk_GetBitmap takes as argument a Tk_Uid describing a bitmap. It returns a Pixmap identifier for a bitmap corresponding to the description. It re-uses an existing bitmap, if possible, and creates a new one otherwise. At present, id must have one of the following forms:
|
@fileName |
FileName must be the name of a file containing a bitmap description in the standard X11 or X10 format. | ||
|
name |
Name must be the name of a bitmap defined previously with a call to Tk_DefineBitmap. The following names are pre-defined by Tk: |
error
|
The international "don’t" symbol: a circle with a diagonal line across it. |
gray75 │
75% gray: a checkerboard pattern where │ three out of four bits are on.
|
gray50 |
50% gray: a checkerboard pattern where every other bit is on. |
gray25 │
25% gray: a checkerboard pattern where │ one out of every four bits is on.
|
gray12 |
12.5% gray: a pattern where one-eighth of the bits are on, consisting of every fourth pixel in every other row. | ||
|
hourglass |
An hourglass symbol. | ||
|
info |
A large letter ’’i’’. | ||
|
questhead |
The silhouette of a human head, with a question mark in it. | ||
|
question |
A large question-mark. | ||
|
warning |
A large exclamation point. |
In addition, the following pre-defined names are available only on the Macintosh platform:
|
document |
A generic document. | ||
|
stationery |
Document stationery. | ||
|
edition |
The edition symbol. | ||
|
application |
Generic application icon. | ||
|
accessory |
A desk accessory. | ||
|
folder |
Generic folder icon. | ||
|
pfolder |
A locked folder. | ||
|
trash |
A trash can. | ||
|
floppy |
A floppy disk. | ||
|
ramdisk |
A floppy disk with chip. | ||
|
cdrom |
A cd disk icon. | ||
|
preferences |
A folder with prefs symbol. | ||
|
querydoc |
A database document icon. | ||
|
stop |
A stop sign. | ||
|
note |
A face with ballon words. | ||
|
caution |
A triangle with an exclamation point. |
Under normal conditions, Tk_GetBitmap returns an identifier for the requested bitmap. If an error occurs in creating the bitmap, such as when id refers to a non-existent file, then None is returned and an error message is left in interp->result.
Tk_DefineBitmap associates a name with in-memory bitmap data so that the name can be used in later calls to Tk_GetBitmap. The nameId argument gives a name for the bitmap; it must not previously have been used in a call to Tk_DefineBitmap. The arguments source, width, and height describe the bitmap. Tk_DefineBitmap normally returns TCL_OK; if an error occurs (e.g. a bitmap named nameId has already been defined) then TCL_ERROR is returned and an error message is left in interp->result. Note: Tk_DefineBitmap expects the memory pointed to by source to be static: Tk_DefineBitmap doesn’t make a private copy of this memory, but uses the bytes pointed to by source later in calls to Tk_GetBitmap.
Typically Tk_DefineBitmap is used by #include-ing a bitmap file directly into a C program and then referencing the variables defined by the file. For example, suppose there exists a file stip.bitmap, which was created by the bitmap program and contains a stipple pattern. The following code uses Tk_DefineBitmap to define a new bitmap named foo:
Pixmap bitmap;
#include "stip.bitmap"
Tk_DefineBitmap(interp, Tk_GetUid("foo"),
stip_bits,
|
stip_width, stip_height); |
...
bitmap = Tk_GetBitmap(interp, tkwin,
Tk_GetUid("foo"));
This code causes the bitmap file to be read at compile-time and incorporates the bitmap information into the program’s executable image. The same bitmap file could be read at run-time using Tk_GetBitmap:
Pixmap bitmap;
bitmap = Tk_GetBitmap(interp, tkwin,
Tk_GetUid("@stip.bitmap"));
The second form is a bit more flexible (the file could be modified after the program has been compiled, or a different string could be provided to read a different file), but it is a little slower and requires the bitmap file to exist separately from the program.
Tk_GetBitmap maintains a database of all the bitmaps that are currently in use. Whenever possible, it will return an existing bitmap rather than creating a new one. This approach can substantially reduce server overhead, so Tk_GetBitmap should generally be used in preference to Xlib procedures like XReadBitmapFile.
The bitmaps returned by Tk_GetBitmap are shared, so callers should never modify them. If a bitmap must be modified dynamically, then it should be created by calling Xlib procedures such as XReadBitmapFile or XCreatePixmap directly.
The procedure Tk_NameOfBitmap is roughly the inverse of Tk_GetBitmap. Given an X Pixmap argument, it returns the id that was passed to Tk_GetBitmap when the bitmap was created. Bitmap must have been the return value from a previous call to Tk_GetBitmap.
Tk_SizeOfBitmap returns the dimensions of its bitmap argument in the words pointed to by the widthPtr and heightPtr arguments. As with Tk_NameOfBitmap, bitmap must have been created by Tk_GetBitmap.
When a bitmap returned by Tk_GetBitmap is no longer needed, Tk_FreeBitmap should be called to release it. There should be exactly one call to Tk_FreeBitmap for each call to Tk_GetBitmap. When a bitmap is no longer in use anywhere (i.e. it has been freed as many times as it has been gotten) Tk_FreeBitmap will release it to the X server and delete it from the database.
In determining whether an existing bitmap can be used to satisfy a new request, Tk_GetBitmap considers only the immediate value of its id argument. For example, when a file name is passed to Tk_GetBitmap, Tk_GetBitmap will assume it is safe to re-use an existing bitmap created from the same file name: it will not check to see whether the file itself has changed, or whether the current directory has changed, thereby causing the name to refer to a different file.
bitmap, pixmap
|
Tk_GetBitmap(3) | |