tkunixscale.c

linux系统下的音频通信


/*
 *----------------------------------------------------------------------
 *
 * DisplayHorizontalValue --
 *
 *	This procedure is called to display values (scale readings)
 *	for horizontally-oriented scales.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The numerical value corresponding to value is displayed with
 *	its bottom edge at "bottom", and at a horizontal position in
 *	the scale that corresponds to "value".
 *
 *----------------------------------------------------------------------
 */

static void
DisplayHorizontalValue(scalePtr, drawable, value, top)
    register TkScale *scalePtr;	/* Information about widget in which to
				 * display value. */
    Drawable drawable;		/* Pixmap or window in which to draw
				 * the value. */
    double value;		/* X-coordinate of number to display,
				 * specified in application coords, not
				 * in pixels (we'll compute pixels). */
    int top;			/* Y-coordinate of top edge of text,
				 * specified in pixels. */
{
    register Tk_Window tkwin = scalePtr->tkwin;
    int x, y, length, width;
    char valueString[PRINT_CHARS];
    Tk_FontMetrics fm;

    x = TkpValueToPixel(scalePtr, value);
    Tk_GetFontMetrics(scalePtr->tkfont, &fm);
    y = top + fm.ascent;
    sprintf(valueString, scalePtr->format, value);
    length = strlen(valueString);
    width = Tk_TextWidth(scalePtr->tkfont, valueString, length);

    /*
     * Adjust the x-coordinate if necessary to keep the text entirely
     * inside the window.
     */

    x -= (width)/2;
    if (x < (scalePtr->inset + SPACING)) {
	x = scalePtr->inset + SPACING;
    }
    if (x > (Tk_Width(tkwin) - scalePtr->inset)) {
	x = Tk_Width(tkwin) - scalePtr->inset - SPACING - width;
    }
    Tk_DrawChars(scalePtr->display, drawable, scalePtr->textGC,
	    scalePtr->tkfont, valueString, length, x, y);
}

/*
 *----------------------------------------------------------------------
 *
 * TkpDisplayScale --
 *
 *	This procedure is invoked as an idle handler to redisplay
 *	the contents of a scale widget.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The scale gets redisplayed.
 *
 *----------------------------------------------------------------------
 */

void
TkpDisplayScale(clientData)
    ClientData clientData;	/* Widget record for scale. */
{
    TkScale *scalePtr = (TkScale *) clientData;
    Tk_Window tkwin = scalePtr->tkwin;
    Tcl_Interp *interp = scalePtr->interp;
    Pixmap pixmap;
    int result;
    char string[PRINT_CHARS];
    XRectangle drawnArea;

    if ((scalePtr->tkwin == NULL) || !Tk_IsMapped(scalePtr->tkwin)) {
	goto done;
    }

    /*
     * Invoke the scale's command if needed.
     */

    Tcl_Preserve((ClientData) scalePtr);
    Tcl_Preserve((ClientData) interp);
    if ((scalePtr->flags & INVOKE_COMMAND) && (scalePtr->command != NULL)) {
	sprintf(string, scalePtr->format, scalePtr->value);
	result = Tcl_VarEval(interp, scalePtr->command,	" ", string,
                             (char *) NULL);
	if (result != TCL_OK) {
	    Tcl_AddErrorInfo(interp, "\n    (command executed by scale)");
	    Tcl_BackgroundError(interp);
	}
    }
    Tcl_Release((ClientData) interp);
    scalePtr->flags &= ~INVOKE_COMMAND;
    if (scalePtr->tkwin == NULL) {
	Tcl_Release((ClientData) scalePtr);
	return;
    }
    Tcl_Release((ClientData) scalePtr);

    /*
     * In order to avoid screen flashes, this procedure redraws
     * the scale in a pixmap, then copies the pixmap to the
     * screen in a single operation.  This means that there's no
     * point in time where the on-sreen image has been cleared.
     */

    pixmap = Tk_GetPixmap(scalePtr->display, Tk_WindowId(tkwin),
	    Tk_Width(tkwin), Tk_Height(tkwin), Tk_Depth(tkwin));
    drawnArea.x = 0;
    drawnArea.y = 0;
    drawnArea.width = Tk_Width(tkwin);
    drawnArea.height = Tk_Height(tkwin);

    /*
     * Much of the redisplay is done totally differently for
     * horizontal and vertical scales.  Handle the part that's
     * different.
     */

    if (scalePtr->vertical) {
	DisplayVerticalScale(scalePtr, pixmap, &drawnArea);
    } else {
	DisplayHorizontalScale(scalePtr, pixmap, &drawnArea);
    }

    /*
     * Now handle the part of redisplay that is the same for
     * horizontal and vertical scales:  border and traversal
     * highlight.
     */

    if (scalePtr->flags & REDRAW_OTHER) {
	if (scalePtr->relief != TK_RELIEF_FLAT) {
	    Tk_Draw3DRectangle(tkwin, pixmap, scalePtr->bgBorder,
		    scalePtr->highlightWidth, scalePtr->highlightWidth,
		    Tk_Width(tkwin) - 2*scalePtr->highlightWidth,
		    Tk_Height(tkwin) - 2*scalePtr->highlightWidth,
		    scalePtr->borderWidth, scalePtr->relief);
	}
	if (scalePtr->highlightWidth != 0) {
	    GC gc;
    
	    if (scalePtr->flags & GOT_FOCUS) {
		gc = Tk_GCForColor(scalePtr->highlightColorPtr, pixmap);
	    } else {
		gc = Tk_GCForColor(scalePtr->highlightBgColorPtr, pixmap);
	    }
	    Tk_DrawFocusHighlight(tkwin, gc, scalePtr->highlightWidth, pixmap);
	}
    }

    /*
     * Copy the information from the off-screen pixmap onto the screen,
     * then delete the pixmap.
     */

    XCopyArea(scalePtr->display, pixmap, Tk_WindowId(tkwin),
	    scalePtr->copyGC, drawnArea.x, drawnArea.y, drawnArea.width,
	    drawnArea.height, drawnArea.x, drawnArea.y);
    Tk_FreePixmap(scalePtr->display, pixmap);

    done:
    scalePtr->flags &= ~REDRAW_ALL;
}

/*
 *----------------------------------------------------------------------
 *
 * TkpScaleElement --
 *
 *	Determine which part of a scale widget lies under a given
 *	point.
 *
 * Results:
 *	The return value is either TROUGH1, SLIDER, TROUGH2, or
 *	OTHER, depending on which of the scale's active elements
 *	(if any) is under the point at (x,y).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkpScaleElement(scalePtr, x, y)
    TkScale *scalePtr;		/* Widget record for scale. */
    int x, y;			/* Coordinates within scalePtr's window. */
{
    int sliderFirst;

    if (scalePtr->vertical) {
	if ((x < scalePtr->vertTroughX)
		|| (x >= (scalePtr->vertTroughX + 2*scalePtr->borderWidth +
		scalePtr->width))) {
	    return OTHER;
	}
	if ((y < scalePtr->inset)
		|| (y >= (Tk_Height(scalePtr->tkwin) - scalePtr->inset))) {
	    return OTHER;
	}
	sliderFirst = TkpValueToPixel(scalePtr, scalePtr->value)
		- scalePtr->sliderLength/2;
	if (y < sliderFirst) {
	    return TROUGH1;
	}
	if (y < (sliderFirst+scalePtr->sliderLength)) {
	    return SLIDER;
	}
	return TROUGH2;
    }

    if ((y < scalePtr->horizTroughY)
	    || (y >= (scalePtr->horizTroughY + 2*scalePtr->borderWidth +
	    scalePtr->width))) {
	return OTHER;
    }
    if ((x < scalePtr->inset)
	    || (x >= (Tk_Width(scalePtr->tkwin) - scalePtr->inset))) {
	return OTHER;
    }
    sliderFirst = TkpValueToPixel(scalePtr, scalePtr->value)
	    - scalePtr->sliderLength/2;
    if (x < sliderFirst) {
	return TROUGH1;
    }
    if (x < (sliderFirst+scalePtr->sliderLength)) {
	return SLIDER;
    }
    return TROUGH2;
}

/*
 *--------------------------------------------------------------
 *
 * TkpSetScaleValue --
 *
 *	This procedure changes the value of a scale and invokes
 *	a Tcl command to reflect the current position of a scale
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A Tcl command is invoked, and an additional error-processing
 *	command may also be invoked.  The scale's slider is redrawn.
 *
 *--------------------------------------------------------------
 */

void
TkpSetScaleValue(scalePtr, value, setVar, invokeCommand)
    register TkScale *scalePtr;	/* Info about widget. */
    double value;		/* New value for scale.  Gets adjusted
				 * if it's off the scale. */
    int setVar;			/* Non-zero means reflect new value through
				 * to associated variable, if any. */
    int invokeCommand;		/* Non-zero means invoked -command option
				 * to notify of new value, 0 means don't. */
{
    char string[PRINT_CHARS];

    value = TkRoundToResolution(scalePtr, value);
    if ((value < scalePtr->fromValue)
	    ^ (scalePtr->toValue < scalePtr->fromValue)) {
	value = scalePtr->fromValue;
    }
    if ((value > scalePtr->toValue)
	    ^ (scalePtr->toValue < scalePtr->fromValue)) {
	value = scalePtr->toValue;
    }
    if (scalePtr->flags & NEVER_SET) {
	scalePtr->flags &= ~NEVER_SET;
    } else if (scalePtr->value == value) {
	return;
    }
    scalePtr->value = value;
    if (invokeCommand) {
	scalePtr->flags |= INVOKE_COMMAND;
    }
    TkEventuallyRedrawScale(scalePtr, REDRAW_SLIDER);

    if (setVar && (scalePtr->varName != NULL)) {
	sprintf(string, scalePtr->format, scalePtr->value);
	scalePtr->flags |= SETTING_VAR;
	Tcl_SetVar(scalePtr->interp, scalePtr->varName, string,
	       TCL_GLOBAL_ONLY);
	scalePtr->flags &= ~SETTING_VAR;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkpPixelToValue --
 *
 *	Given a pixel within a scale window, return the scale
 *	reading corresponding to that pixel.
 *
 * Results:
 *	A double-precision scale reading.  If the value is outside
 *	the legal range for the scale then it's rounded to the nearest
 *	end of the scale.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

double
TkpPixelToValue(scalePtr, x, y)
    register TkScale *scalePtr;		/* Information about widget. */
    int x, y;				/* Coordinates of point within
					 * window. */
{
    double value, pixelRange;

    if (scalePtr->vertical) {
	pixelRange = Tk_Height(scalePtr->tkwin) - scalePtr->sliderLength
		- 2*scalePtr->inset - 2*scalePtr->borderWidth;
	value = y;
    } else {
	pixelRange = Tk_Width(scalePtr->tkwin) - scalePtr->sliderLength
		- 2*scalePtr->inset - 2*scalePtr->borderWidth;
	value = x;
    }

    if (pixelRange <= 0) {
	/*
	 * Not enough room for the slider to actually slide:  just return
	 * the scale's current value.
	 */

	return scalePtr->value;
    }
    value -= scalePtr->sliderLength/2 + scalePtr->inset
		+ scalePtr->borderWidth;
    value /= pixelRange;
    if (value < 0) {
	value = 0;
    }
    if (value > 1) {
	value = 1;
    }
    value = scalePtr->fromValue +
		value * (scalePtr->toValue - scalePtr->fromValue);
    return TkRoundToResolution(scalePtr, value);
}

/*
 *----------------------------------------------------------------------
 *
 * TkpValueToPixel --
 *
 *	Given a reading of the scale, return the x-coordinate or
 *	y-coordinate corresponding to that reading, depending on
 *	whether the scale is vertical or horizontal, respectively.
 *
 * Results:
 *	An integer value giving the pixel location corresponding
 *	to reading.  The value is restricted to lie within the
 *	defined range for the scale.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkpValueToPixel(scalePtr, value)
    register TkScale *scalePtr;		/* Information about widget. */
    double value;			/* Reading of the widget. */
{
    int y, pixelRange;
    double valueRange;

    valueRange = scalePtr->toValue - scalePtr->fromValue;
    pixelRange = (scalePtr->vertical ? Tk_Height(scalePtr->tkwin)
	    : Tk_Width(scalePtr->tkwin)) - scalePtr->sliderLength
	    - 2*scalePtr->inset - 2*scalePtr->borderWidth;
    if (valueRange == 0) {
	y = 0;
    } else {
	y = (int) ((value - scalePtr->fromValue) * pixelRange
		  / valueRange + 0.5);
	if (y < 0) {
	    y = 0;
	} else if (y > pixelRange) {
	    y = pixelRange;
	}
    }
    y += scalePtr->sliderLength/2 + scalePtr->inset + scalePtr->borderWidth;
    return y;
}