258 lines
9.5 KiB

* tkCanvas.h --
* Declarations shared among all the files that implement
* canvas widgets.
* Copyright (c) 1991-1994 The Regents of the University of California.
* Copyright (c) 1994-1995 Sun Microsystems, Inc.
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
* SCCS: @(#) tkCanvas.h 1.41 96/02/15 18:51:28
#ifndef _TKCANVAS
#define _TKCANVAS
#ifndef _TK
#include "tk.h"
* The record below describes a canvas widget. It is made available
* to the item procedures so they can access certain shared fields such
* as the overall displacement and scale factor for the canvas.
typedef struct TkCanvas {
Tk_Window tkwin; /* Window that embodies the canvas. NULL
* means that the window has been destroyed
* but the data structures haven't yet been
* cleaned up.*/
Display *display; /* Display containing widget; needed, among
* other things, to release resources after
* tkwin has already gone away. */
Tcl_Interp *interp; /* Interpreter associated with canvas. */
Tcl_Command widgetCmd; /* Token for canvas's widget command. */
Tk_Item *firstItemPtr; /* First in list of all items in canvas,
* or NULL if canvas empty. */
Tk_Item *lastItemPtr; /* Last in list of all items in canvas,
* or NULL if canvas empty. */
* Information used when displaying widget:
int borderWidth; /* Width of 3-D border around window. */
Tk_3DBorder bgBorder; /* Used for canvas background. */
int relief; /* Indicates whether window as a whole is
* raised, sunken, or flat. */
int highlightWidth; /* Width in pixels of highlight to draw
* around widget when it has the focus.
* <= 0 means don't draw a highlight. */
XColor *highlightBgColorPtr;
/* Color for drawing traversal highlight
* area when highlight is off. */
XColor *highlightColorPtr; /* Color for drawing traversal highlight. */
int inset; /* Total width of all borders, including
* traversal highlight and 3-D border.
* Indicates how much interior stuff must
* be offset from outside edges to leave
* room for borders. */
GC pixmapGC; /* Used to copy bits from a pixmap to the
* screen and also to clear the pixmap. */
int width, height; /* Dimensions to request for canvas window,
* specified in pixels. */
int redrawX1, redrawY1; /* Upper left corner of area to redraw,
* in pixel coordinates. Border pixels
* are included. Only valid if
* REDRAW_PENDING flag is set. */
int redrawX2, redrawY2; /* Lower right corner of area to redraw,
* in integer canvas coordinates. Border
* pixels will *not* be redrawn. */
int confine; /* Non-zero means constrain view to keep
* as much of canvas visible as possible. */
* Information used to manage the selection and insertion cursor:
Tk_CanvasTextInfo textInfo; /* Contains lots of fields; see tk.h for
* details. This structure is shared with
* the code that implements individual items. */
int insertOnTime; /* Number of milliseconds cursor should spend
* in "on" state for each blink. */
int insertOffTime; /* Number of milliseconds cursor should spend
* in "off" state for each blink. */
Tcl_TimerToken insertBlinkHandler;
/* Timer handler used to blink cursor on and
* off. */
* Transformation applied to canvas as a whole: to compute screen
* coordinates (X,Y) from canvas coordinates (x,y), do the following:
* X = x - xOrigin;
* Y = y - yOrigin;
int xOrigin, yOrigin; /* Canvas coordinates corresponding to
* upper-left corner of window, given in
* canvas pixel units. */
int drawableXOrigin, drawableYOrigin;
/* During redisplay, these fields give the
* canvas coordinates corresponding to
* the upper-left corner of the drawable
* where items are actually being drawn
* (typically a pixmap smaller than the
* whole window). */
* Information used for event bindings associated with items.
Tk_BindingTable bindingTable;
/* Table of all bindings currently defined
* for this canvas. NULL means that no
* bindings exist, so the table hasn't been
* created. Each "object" used for this
* table is either a Tk_Uid for a tag or
* the address of an item named by id. */
Tk_Item *currentItemPtr; /* The item currently containing the mouse
* pointer, or NULL if none. */
Tk_Item *newCurrentPtr; /* The item that is about to become the
* current one, or NULL. This field is
* used to detect deletions of the new
* current item pointer that occur during
* Leave processing of the previous current
* item. */
double closeEnough; /* The mouse is assumed to be inside an
* item if it is this close to it. */
XEvent pickEvent; /* The event upon which the current choice
* of currentItem is based. Must be saved
* so that if the currentItem is deleted,
* can pick another. */
int state; /* Last known modifier state. Used to
* defer picking a new current object
* while buttons are down. */
* Information used for managing scrollbars:
char *xScrollCmd; /* Command prefix for communicating with
* horizontal scrollbar. NULL means no
* horizontal scrollbar. Malloc'ed*/
char *yScrollCmd; /* Command prefix for communicating with
* vertical scrollbar. NULL means no
* vertical scrollbar. Malloc'ed*/
int scrollX1, scrollY1, scrollX2, scrollY2;
/* These four coordinates define the region
* that is the 100% area for scrolling (i.e.
* these numbers determine the size and
* location of the sliders on scrollbars).
* Units are pixels in canvas coords. */
char *regionString; /* The option string from which scrollX1
* etc. are derived. Malloc'ed. */
int xScrollIncrement; /* If >0, defines a grid for horizontal
* scrolling. This is the size of the "unit",
* and the left edge of the screen will always
* lie on an even unit boundary. */
int yScrollIncrement; /* If >0, defines a grid for horizontal
* scrolling. This is the size of the "unit",
* and the left edge of the screen will always
* lie on an even unit boundary. */
* Information used for scanning:
int scanX; /* X-position at which scan started (e.g.
* button was pressed here). */
int scanXOrigin; /* Value of xOrigin field when scan started. */
int scanY; /* Y-position at which scan started (e.g.
* button was pressed here). */
int scanYOrigin; /* Value of yOrigin field when scan started. */
* Information used to speed up searches by remembering the last item
* created or found with an item id search.
Tk_Item *hotPtr; /* Pointer to "hot" item (one that's been
* recently used. NULL means there's no
* hot item. */
Tk_Item *hotPrevPtr; /* Pointer to predecessor to hotPtr (NULL
* means item is first in list). This is
* only a hint and may not really be hotPtr's
* predecessor. */
* Miscellaneous information:
Tk_Cursor cursor; /* Current cursor for window, or None. */
char *takeFocus; /* Value of -takefocus option; not used in
* the C code, but used by keyboard traversal
* scripts. Malloc'ed, but may be NULL. */
double pixelsPerMM; /* Scale factor between MM and pixels;
* used when converting coordinates. */
int flags; /* Various flags; see below for
* definitions. */
int nextId; /* Number to use as id for next item
* created in widget. */
struct TkPostscriptInfo *psInfoPtr;
/* Pointer to information used for generating
* Postscript for the canvas. NULL means
* no Postscript is currently being
* generated. */
} TkCanvas;
* Flag bits for canvases:
* REDRAW_PENDING - 1 means a DoWhenIdle handler has already
* been created to redraw some or all of the
* canvas.
* REDRAW_BORDERS - 1 means that the borders need to be redrawn
* during the next redisplay operation.
* REPICK_NEEDED - 1 means DisplayCanvas should pick a new
* current item before redrawing the canvas.
* GOT_FOCUS - 1 means the focus is currently in this
* widget, so should draw the insertion cursor
* and traversal highlight.
* CURSOR_ON - 1 means the insertion cursor is in the "on"
* phase of its blink cycle. 0 means either
* we don't have the focus or the cursor is in
* the "off" phase of its cycle.
* UPDATE_SCROLLBARS - 1 means the scrollbars should get updated
* as part of the next display operation.
* LEFT_GRABBED_ITEM - 1 means that the mouse left the current
* item while a grab was in effect, so we
* didn't change canvasPtr->currentItemPtr.
* REPICK_IN_PROGRESS - 1 means PickCurrentItem is currently
* executing. If it should be called recursively,
* it should simply return immediately.
#define GOT_FOCUS 8
#define CURSOR_ON 0x10
#define LEFT_GRABBED_ITEM 0x40
#define REPICK_IN_PROGRESS 0x100
* Canvas-related procedures that are shared among Tk modules but not
* exported to the outside world:
extern int TkCanvPostscriptCmd _ANSI_ARGS_((TkCanvas *canvasPtr,
Tcl_Interp *interp, int argc, char **argv));
#endif /* _TKCANVAS */