Tk Source Code

    Tk_ItemTranslateProc *\fItranslateProc\fR;
    Tk_ItemIndexProc *\fIindexProc\fR;
    Tk_ItemCursorProc *\fIicursorProc\fR;
    Tk_ItemSelectionProc *\fIselectionProc\fR;
    Tk_ItemInsertProc *\fIinsertProc\fR;
    Tk_ItemDCharsProc *\fIdCharsProc\fR;
    Tk_ItemType *\fInextPtr\fR;
.VS "8.7, TIP164"
    Tk_ItemRotateProc *\fIrotateProc\fR;
.VE "8.7, TIP164"
} \fBTk_ItemType\fR;
.CE
.PP
The fields of a Tk_ItemType structure are described in more detail
later in this manual entry.
When \fBTk_CreateItemType\fR is called, its \fItypePtr\fR
argument must point to a structure with all of the fields initialized

.CE
.PP
The \fIcanvas\fR and \fIitemPtr\fR arguments have the usual meaning,
and \fIdeltaX\fR and \fIdeltaY\fR give the amounts that should be
added to each x and y coordinate within the item.
The type manager should adjust the item's coordinates and
update the bounding box in the item's header.
.SS ROTATEPROC
.VS "8.7, TIP164"
.PP
\fItypePtr\->rotateProc\fR is invoked by Tk to rotate a canvas item
during the \fBrotate\fR widget command.
The procedure must match the following prototype:
.PP
.CS
typedef void \fBTk_ItemRotateProc\fR(
        Tk_Canvas \fIcanvas\fR,
        Tk_Item *\fIitemPtr\fR,
        double \fIoriginX\fR,
        double \fIoriginY\fR,
        double \fIangleRad\fR);
.CE
.PP
The \fIcanvas\fR and \fIitemPtr\fR arguments have the usual meaning.
\fIoriginX\fR and \fIoriginY\fR specify an origin relative to which
the item is to be rotated, and \fIangleRad\fR gives the anticlockwise
rotation to be applied in radians.
The item should adjust the coordinates of its control points so that where
they used to have coordinates \fIx\fR and \fIy\fR, they will have new
coordinates \fIx\(fm\fR and \fIy\(fm\fR, where
.PP
.CS
\fIrelX\fR = \fIx\fR - \fIoriginX\fR
\fIrelY\fR = \fIy\fR - \fIoriginY\fR
\fIx\(fm\fR = \fIoriginX\fR + \fIrelX\fR \(mu cos(\fIangleRad\fR) + \fIrelY\fR \(mu sin(\fIangleRad\fR)
\fIy\(fm\fR = \fIoriginY\fR \(mi \fIrelX\fR \(mu sin(\fIangleRad\fR) + \fIrelY\fR \(mu cos(\fIangleRad\fR)
.CE
.PP
The control points for an item are not necessarily the coordinates provided to
the item when it is created (or via the \fItypePtr\->coordProc\fR), but could
instead be derived from them.
\fIrotateProc\fR must also update the bounding box in the item's header.
.PP
Item types do not need to provide a \fItypePtr\->rotateProc\fR. If the
\fItypePtr\->rotateProc\fR is NULL, the \fItypePtr\->coordProc\fR will be
used instead to retrieve and update the list of coordinates.
.VE "8.7, TIP164"
.SS INDEXPROC
.PP
\fItypePtr\->indexProc\fR is invoked by Tk to translate a string
index specification into a numerical index, for example during the
\fBindex\fR widget command.
It is only relevant for item types that support indexable text or coordinates;
\fItypePtr\->indexProc\fR may be specified as NULL for non-textual

It is possible to adjust the origin of the canvas
coordinate system relative to the origin of the window using the
\fBxview\fR and \fByview\fR widget commands; this is typically used
for scrolling.
Canvases do not support scaling or rotation of the canvas coordinate
system relative to the window coordinate system.
.PP
Individual items may be moved, scaled
.VS "8.7, TIP164"
or rotated
.VE "8.7, TIP164"
using widget commands
described below.
.PP
Note that the default origin of the canvas's visible area is
coincident with the origin for the whole window as that makes bindings
using the mouse position easier to work with; you only need to use the
\fBcanvasx\fR and \fBcanvasy\fR widget commands if you adjust the
origin of the visible area. However, this also means that any focus
ring (as controlled by the \fB\-highlightthickness\fR option) and

factor can also be given and the photo image will be enlarged. The image background
will be filled with the canvas background colour. The canvas widget does not need to
be mapped for this widget command to work, but at least one of it's ancestors must be
mapped.
This command returns an empty string.
.TP
\fIpathName \fBimove \fItagOrId index x y\fR

.
This command causes the \fIindex\fR'th coordinate of each of the items
indicated by \fItagOrId\fR to be relocated to the location (\fIx\fR,\fIy\fR).
Each item interprets \fIindex\fR independently according to the rules
described in \fBINDICES\fR above. Out of the standard set of items, only line
and polygon items may have their coordinates relocated this way.

.TP
\fIpathName \fBindex \fItagOrId index\fR
.
This command returns a decimal string giving the numerical index
within \fItagOrId\fR corresponding to \fIindex\fR.
\fIIndex\fR gives a textual description of the desired position
as described in \fBINDICES\fR above.

Move each of the items given by \fItagOrId\fR in the canvas coordinate
space by adding \fIxAmount\fR to the x-coordinate of each point
associated with the item and \fIyAmount\fR to the y-coordinate of
each point associated with the item.
This command returns an empty string.
.TP
\fIpathName \fBmoveto \fItagOrId xPos yPos\fR

.
Move the items given by \fItagOrId\fR in the canvas coordinate
space so that the first coordinate pair of the bottommost item with
tag \fItagOrId\fR is located at
position (\fIxPos\fR,\fIyPos\fR). \fIxPos\fR and \fIyPos\fR may be
the empty string, in which case the corresponding coordinate
will be unchanged. All items matching
\fItagOrId\fR remain in the same positions relative to each other.
This command returns an empty string.

.TP
\fIpathName \fBpostscript \fR?\fIoption value option value ...\fR?
.
Generate a Postscript representation for part or all of the canvas.
If the \fB\-file\fR option is specified then the Postscript is written
to a file and an empty string is returned; otherwise the Postscript
is returned as the result of the command.

Note: this command has no effect on window items. Window items always
obscure other item types, and the stacking order of window items is
determined by the \fBraise\fR command and \fBlower\fR command, not the
\fBraise\fR widget command and \fBlower\fR widget command for canvases.
.RE
.TP
\fIpathName \fBrchars \fItagOrId first last string\fR

.
This command causes the text or coordinates between \fIfirst\fR and \fIlast\fR
for each of the items indicated by \fItagOrId\fR to be replaced by
\fIstring\fR. Each item interprets \fIfirst\fR and \fIlast\fR independently
according to the rules described in \fBINDICES\fR above. Out of the standard
set of items, text items support this operation by altering their text as
directed, and line and polygon items support this operation by altering their
coordinate list (in which case \fIstring\fR should be a list of coordinates to
use as a replacement). The other items ignore this operation.
.TP
\fIpathName \fBrotate \fItagOrId xOrigin yOrigin angle\fR
.VS "8.7, TIP164"
Rotate the coordinates of all of the items given by \fItagOrId\fR in canvas
coordinate space.
\fIXOrigin\fR and \fIyOrigin\fR identify the origin for the rotation
operation and \fIangle\fR identifies the amount to rotate the coordinates
anticlockwise, in degrees. (Negative values rotate clockwise.)
This command returns an empty string.
.RS
.PP
Implementation note: not all item types work well with rotations. In
particular, the \fBarc\fR, \fBoval\fR and \fBrectangle\fR types are very
unlikely to work as you expect. Several other item types only have a single
coordinate; this command can move that anchor point, but will not rotate the
item about that anchor point.
.RE
.VE "8.7, TIP164"
.TP
\fIpathName \fBscale \fItagOrId xOrigin yOrigin xScale yScale\fR
.
Rescale the coordinates of all of the items given by \fItagOrId\fR in canvas
coordinate space.
\fIXOrigin\fR and \fIyOrigin\fR identify the origin for the scaling
operation and \fIxScale\fR and \fIyScale\fR identify the scale

\fB\-stipple\fR	\fB\-activestipple\fR
\fB\-disabledstipple\fR	\fB\-state\fR
\fB\-tags\fR
.DE
The following extra options are supported for text items:
.TP
\fB\-angle \fIrotationDegrees\fR

.
\fIRotationDegrees\fR tells how many degrees to rotate the text anticlockwise
about the positioning point for the text; it may have any floating-point value
from 0.0 to 360.0. For example, if \fIrotationDegrees\fR is \fB90\fR, then the
text will be drawn vertically from bottom to top.
This option defaults to \fB0.0\fR.

.TP
\fB\-font \fIfontName\fR
Specifies the font to use for the text item.
\fIFontName\fR may be any string acceptable to \fBTk_GetFont\fR.
If this option is not specified, it defaults to a system-dependent
font.
.TP

    Tk_Canvas canvas,
    Tk_Item *itemPtr,
    double originX,
    double originY,
    double angleRad)
{
    ArcItem *arcPtr = (ArcItem *) itemPtr;

    double s = sin(angleRad), c = cos(angleRad);
    double coords[4];

    memcpy(coords, arcPtr->bbox, sizeof(coords));
    TkRotatePoint(originX, originY, s, c, &coords[0], &coords[1]);


    TkRotatePoint(originX, originY, s, c, &coords[2], &coords[3]);

    /*
     * Sort the points for the bounding box.
     */

    arcPtr->bbox[0] = (coords[0] < coords[2]) ? coords[0] : coords[2];
    arcPtr->bbox[1] = (coords[1] < coords[3]) ? coords[1] : coords[3];


    arcPtr->bbox[2] = (coords[0] < coords[2]) ? coords[2] : coords[0];
    arcPtr->bbox[3] = (coords[1] < coords[3]) ? coords[3] : coords[1];

    /*
     * TODO: update the arc endpoints?
     */

    ComputeArcBbox(canvas, arcPtr);
}

    Tk_Canvas canvas,
    Tk_Item *itemPtr,
    double originX,
    double originY,
    double angleRad)
{
    BitmapItem *bmapPtr = (BitmapItem *) itemPtr;





    TkRotatePoint(originX, originY, sin(angleRad), cos(angleRad),


	    &bmapPtr->x, &bmapPtr->y);

    ComputeBitmapBbox(canvas, bmapPtr);
}

/*
 *--------------------------------------------------------------
 *
 * TranslateBitmap --

    Tk_Canvas canvas,
    Tk_Item *itemPtr,
    double originX,
    double originY,
    double angleRad)
{
    ImageItem *imgPtr = (ImageItem *) itemPtr;





    TkRotatePoint(originX, originY, sin(angleRad), cos(angleRad),


	    &imgPtr->x, &imgPtr->y);

    ComputeImageBbox(canvas, imgPtr);
}

/*
 *--------------------------------------------------------------
 *
 * ScaleImage --

 *	The position of the line is rotated by angleRad about (originX,
 *	originY), and the bounding box is updated in the generic part of the
 *	item structure.
 *
 *--------------------------------------------------------------
 */














static void
RotateLine(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item that is being moved. */
    double originX, double originY,
    double angleRad)		/* Amount by which item is to be rotated. */
{
    LineItem *linePtr = (LineItem *) itemPtr;
    double *coordPtr;
    int i;
    double s = sin(angleRad), c = cos(angleRad);

    for (i = 0, coordPtr = linePtr->coordPtr; i < linePtr->numPoints;
	    i++, coordPtr += 2) {
	TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
    }
    if (linePtr->firstArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->firstArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
	}
    }
    if (linePtr->lastArrowPtr != NULL) {
	for (i = 0, coordPtr = linePtr->lastArrowPtr; i < PTS_IN_ARROW;
		i++, coordPtr += 2) {
	    TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);
	}
    }
    ComputeLineBbox(canvas, linePtr);
}

/*
 *--------------------------------------------------------------

    PolygonItem *polyPtr = (PolygonItem *) itemPtr;
    double *coordPtr;
    int i;
    double s = sin(angleRad), c = cos(angleRad);

    for (i = 0, coordPtr = polyPtr->coordPtr; i < polyPtr->numPoints;
	    i++, coordPtr += 2) {


	TkRotatePoint(originX, originY, s, c, &coordPtr[0], &coordPtr[1]);


    }
    ComputePolygonBbox(canvas, polyPtr);
}

/*
 *--------------------------------------------------------------
 *

RotateText(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item that is being rotated. */
    double originX, double originY,
    double angleRad)		/* Amount by which item is to be rotated. */
{
    TextItem *textPtr = (TextItem *) itemPtr;




    TkRotatePoint(originX, originY, sin(angleRad), cos(angleRad),
	    &textPtr->x, &textPtr->y);
    ComputeTextBbox(canvas, textPtr);
}

/*
 *--------------------------------------------------------------
 *
 * ScaleText --

	Tk_CanvasSetOffset(canvas, outline->gc, tsoffset);
	tsoffset->xoffset += w;
	tsoffset->yoffset += h;
	return 1;
    }
    return 0;
}


/*
 *--------------------------------------------------------------
 *
 * Tk_ResetOutlineGC
 *
 *	Restores the GC to the situation before Tk_ChangeOutlineGC() was

	TranslateAndAppendCoords(canvPtr, a[i*2], a[i*2+1], outArr, i);
    }
    if (tempArr != staticSpace) {
	ckfree(tempArr);
    }
    return numOutput;
}

/*
 *--------------------------------------------------------------
 *
 * TkRotatePoint --
 *
 *	Rotate a point about another point. The angle should be converted into
 *	its sine and cosine before calling this function.
 *
 * Results:
 *	None
 *
 * Side effects:
 *	The point in (*xPtr,*yPtr) is updated to be rotated about
 *	(originX,originY) by the amount given by the sine and cosine of the
 *	angle to rotate.
 *
 *--------------------------------------------------------------
 */

void
TkRotatePoint(
    double originX, double originY,	/* The point about which to rotate. */
    double sine, double cosine,		/* How much to rotate? */
    double *xPtr, double *yPtr)		/* The point to be rotated. (INOUT) */
{
    double x = *xPtr - originX;
    double y = *yPtr - originY;

    /*
     * Beware! The canvas coordinate space is flipped vertically, so rotations
     * go the "wrong" way with respect to mathematics.
     */

    *xPtr = originX + x * cosine + y * sine;
    *yPtr = originY - x * sine + y * cosine;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */

RotateWinItem(
    Tk_Canvas canvas,		/* Canvas containing item. */
    Tk_Item *itemPtr,		/* Item that is being rotated. */
    double originX, double originY,
    double angleRad)		/* Amount by which item is to be rotated. */
{
    WindowItem *winItemPtr = (WindowItem *) itemPtr;




    TkRotatePoint(originX, originY, sin(angleRad), cos(angleRad),
	    &winItemPtr->x, &winItemPtr->y);
    ComputeWindowBbox(canvas, winItemPtr);
}

/*
 *--------------------------------------------------------------
 *
 * ScaleWinItem --

MODULE_SCOPE int	TkInitFontchooser(Tcl_Interp *interp,
			    ClientData clientData);
MODULE_SCOPE void	TkpWarpPointer(TkDisplay *dispPtr);
MODULE_SCOPE void	TkpCancelWarp(TkDisplay *dispPtr);
MODULE_SCOPE int	TkListCreateFrame(ClientData clientData,
			    Tcl_Interp *interp, Tcl_Obj *listObj,
			    int toplevel, Tcl_Obj *nameObj);
MODULE_SCOPE void	TkRotatePoint(double originX, double originY,
			    double sine, double cosine, double *xPtr,
			    double *yPtr);

#ifdef _WIN32
#define TkParseColor XParseColor
#else
MODULE_SCOPE Status TkParseColor (Display * display,
				Colormap map, const char* spec,
				XColor * colorPtr);

 *	The position of the rectangle or oval is rotated by angleRad about
 *	(originX, originY), and the bounding box is updated in the generic
 *	part of the item structure.
 *
 *--------------------------------------------------------------
 */














static void
RotateRectOval(
    Tk_Canvas canvas,		/* Canvas containing rectangle. */
    Tk_Item *itemPtr,		/* Rectangle to be scaled. */
    double originX, double originY,
				/* Origin about which to rotate rect. */
    double angleRad)		/* Amount to scale in X direction. */
{
    RectOvalItem *rectOvalPtr = (RectOvalItem *) itemPtr;
    double s = sin(angleRad), c = cos(angleRad);
    double coords[4];

    memcpy(coords, rectOvalPtr->bbox, sizeof(coords));
    TkRotatePoint(originX, originY, s, c, &coords[0], &coords[1]);
    TkRotatePoint(originX, originY, s, c, &coords[2], &coords[3]);

    /*
     * Sort the points for the bounding box.
     */

    rectOvalPtr->bbox[0] = (coords[0] < coords[2]) ? coords[0] : coords[2];
    rectOvalPtr->bbox[1] = (coords[1] < coords[3]) ? coords[1] : coords[3];
    rectOvalPtr->bbox[2] = (coords[0] < coords[2]) ? coords[2] : coords[0];
    rectOvalPtr->bbox[3] = (coords[1] < coords[3]) ? coords[3] : coords[1];
    ComputeRectOvalBbox(canvas, rectOvalPtr);
}

/*
 *--------------------------------------------------------------
 *
 * ScaleRectOval --