Tk Source Code

 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tkInt.h"
#include "tkCanvas.h"

#include "float.h"

/*
 * The structure below defines the record for each arc item.
 */

typedef enum {
    PIESLICE_STYLE, CHORD_STYLE, ARC_STYLE
} Style;

 * Prototypes for functions defined in this file:
 */

static void		ComputeArcBbox(Tk_Canvas canvas, ArcItem *arcPtr);
static int		ConfigureArc(Tcl_Interp *interp,
			    Tk_Canvas canvas, Tk_Item *itemPtr, int objc,
			    Tcl_Obj *const objv[], int flags);
static void		ComputeArcFromHeight(ArcItem *arcPtr);
static void		ComputeArcParametersFromHeight(ArcItem *arcPtr);
static int		CreateArc(Tcl_Interp *interp,
			    Tk_Canvas canvas, struct Tk_Item *itemPtr,
			    int objc, Tcl_Obj *const objv[]);
static void		DeleteArc(Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display);
static void		DisplayArc(Tk_Canvas canvas,
			    Tk_Item *itemPtr, Display *display, Drawable dst,

	    arcPtr->activeFillStipple != None) {
	itemPtr->redraw_flags |= TK_ITEM_STATE_DEPENDANT;
    } else {
	itemPtr->redraw_flags &= ~TK_ITEM_STATE_DEPENDANT;
    }

    /*
     * If either the height is provided then the start and extent will be
     * Override the start and extent if the height is given.
     * overridden.
     */
    if (arcPtr->height != 0) {
	ComputeArcFromHeight(arcPtr);

    ComputeArcParametersFromHeight(arcPtr);
	ComputeArcBbox(canvas, arcPtr);
    }
    
    ComputeArcBbox(canvas, arcPtr);

    i = (int) (arcPtr->start/360.0);
    arcPtr->start -= i*360.0;
    if (arcPtr->start < 0) {
	arcPtr->start += 360.0;
    }
    i = (int) (arcPtr->extent/360.0);

    ComputeArcBbox(canvas, arcPtr);
    return TCL_OK;
}

/*
 *--------------------------------------------------------------
 *
 * ComputeArcFromHeight --
 * ComputeArcParametersFromHeight --
 *
 *	This function calculates the arc parameters given start-point,
 *	end-point and height (!= 0).
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The height parameter is set to 0 on exit.
 *
 *--------------------------------------------------------------
 */

static void
ComputeArcFromHeight(
ComputeArcParametersFromHeight(
    ArcItem* arcPtr)
{
    double chordLen, chordDir[2], chordCen[2], arcCen[2], d, radToDeg, radius;

    /*
     * Do nothing if no height has been specified.
     */
     * The chord.

    if (arcPtr->height == 0)
        return;

    /*
     * Calculate the chord length, return early if it is too small.
     */

    chordLen = hypot(arcPtr->endPoint[1] - arcPtr->startPoint[1],
	    arcPtr->startPoint[0] - arcPtr->endPoint[0]);

    if (chordLen < DBL_EPSILON) {
        arcPtr->start = arcPtr->extent = arcPtr->height = 0;
        return;
    }

    chordDir[0] = (arcPtr->endPoint[0] - arcPtr->startPoint[0]) / chordLen;
    chordDir[1] = (arcPtr->endPoint[1] - arcPtr->startPoint[1]) / chordLen;
    chordCen[0] = (arcPtr->startPoint[0] + arcPtr->endPoint[0]) / 2;
    chordCen[1] = (arcPtr->startPoint[1] + arcPtr->endPoint[1]) / 2;

    /*
     * Calculate the radius (assumes height != 0).

	arcPtr->bbox[2] = arcPtr->bbox[0];
	arcPtr->bbox[0] = tmp;
    }

    ComputeArcOutline(canvas,arcPtr);

    /*
     * To compute the bounding box, start with the the bbox formed by the two
     * To compute the bounding box, start with the bbox formed by the two
     * endpoints of the arc. Then add in the center of the arc's oval (if
     * relevant) and the 3-o'clock, 6-o'clock, 9-o'clock, and 12-o'clock
     * positions, if they are relevant.
     */

    arcPtr->header.x1 = arcPtr->header.x2 = (int) arcPtr->center1[0];
    arcPtr->header.y1 = arcPtr->header.y2 = (int) arcPtr->center1[1];

        {#c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0} \
        {#c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0} \
        {#c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0 #c0c0c0}}
} -cleanup {
    destroy .c
    image delete testimage
} -result 1

test canvas-21.1 {canvas very small arc} -setup {
    catch {destroy .c}
    canvas .c
} -body {
    # no Inf or NaN must be generated even for very small arcs
    .c create arc 0 100 0 100 -height 100 -style arc -outline "" -tags arc1
    set arcBox [.c bbox arc1]
    .c create arc 0 100 0 100 -height 100 -style arc -outline blue -tags arc2
    set outlinedArcBox [.c bbox arc2]
    set coords [.c coords arc1]
    set start [.c itemcget arc1 -start]
    set extent [.c itemcget arc1 -extent]
    set width [.c itemcget arc1 -width]
    set height [.c itemcget arc1 -height]
    list $arcBox $outlinedArcBox $coords $start $extent $width $height
} -result {{-1 99 1 101} {-2 98 2 102} {0.0 100.0 0.0 100.0} 0.0 0.0 1.0 0.0}


# cleanup
imageCleanup
cleanupTests
return

# Local Variables: