// Constructor.
public DrawingGraphics(IToolkit toolkit, Xsharp.Graphics graphics)
: base(toolkit)
{
this.graphics = graphics;
this.font = null;
this.gaveHdc = false;
}
// Constructor.
public DrawingGraphics(IToolkit toolkit, Xsharp.Graphics graphics)
: base(toolkit)
{
this.graphics = graphics;
this.font = null;
this.gaveHdc = false;
}
// Select this brush into a graphics object.
public override void Select(IToolkitGraphics _graphics)
{
DrawingGraphics graphics = (_graphics as DrawingGraphics);
if (graphics != null)
{
Xsharp.Graphics g = graphics.graphics;
Xsharp.Bitmap bitmap;
lock (typeof(DrawingHatchBrush))
{
bitmap = GetBitmap(style);
}
g.Function = GCFunction.GXcopy;
g.SubwindowMode = SubwindowMode.ClipByChildren;
if (bitmap != null)
{
// Use an opaque stipple to fill the region.
g.Foreground =
DrawingToolkit.DrawingToXColor(foreColor);
g.Background =
DrawingToolkit.DrawingToXColor(backColor);
g.SetFillOpaqueStippled(bitmap, 0, 0);
}
else
{
// We don't recognize this hatch style, so use a
// solid brush with the foreground color.
g.Foreground =
DrawingToolkit.DrawingToXColor(foreColor);
g.SetFillSolid();
}
graphics.Brush = this;
}
}
// Dispose of this object.
protected override void Dispose(bool disposing)
{
if (graphics != null)
{
graphics.Dispose();
graphics = null;
}
}
// Dispose of this object.
protected override void Dispose(bool disposing)
{
if(graphics != null)
{
graphics.Dispose();
graphics = null;
}
}
// Select this brush into a graphics object.
public override void Select(IToolkitGraphics _graphics)
{
innerBrush.Select(_graphics);
DrawingGraphics graphics = (_graphics as DrawingGraphics);
if (graphics != null)
{
Xsharp.Graphics g = graphics.graphics;
g.Function = GCFunction.GXxor;
g.SubwindowMode = SubwindowMode.IncludeInferiors;
}
graphics.Brush = this;
}
// Handle a paint event from Xsharp.
protected override void OnPaint(Xsharp.Graphics graphics)
{
if (sink != null)
{
System.Drawing.Region clip = RegionToDrawingRegion(graphics.ExposeRegion);
DrawingGraphics g = new DrawingGraphics(toolkit, graphics);
using (System.Drawing.Graphics gr =
ToolkitManager.CreateGraphics(g, clip))
{
sink.ToolkitExpose(gr);
}
}
}
// Select this brush into a graphics object.
public override void Select(IToolkitGraphics _graphics)
{
DrawingGraphics graphics = (_graphics as DrawingGraphics);
if (graphics != null)
{
Xsharp.Graphics g = graphics.graphics;
g.Function = GCFunction.GXcopy;
g.SubwindowMode = SubwindowMode.ClipByChildren;
g.SetFillSolid();
g.Foreground = DrawingToolkit.DrawingToXColor(Color);
graphics.Brush = this;
}
}
// Select this brush into a graphics object.
public void Select(IToolkitGraphics _graphics)
{
DrawingGraphics graphics = (_graphics as DrawingGraphics);
if (graphics != null && image != null)
{
Xsharp.Graphics g = graphics.graphics;
Xsharp.Image nativeImage = image.GetNativeImage();
g.Function = GCFunction.GXcopy;
g.SubwindowMode = SubwindowMode.ClipByChildren;
g.SetFillTiled(nativeImage.Pixmap,
(int)(dstRect.X), (int)(dstRect.Y));
}
}
// Convert an XImage mask into a Bitmap object.
public static Bitmap XImageMaskToBitmap(Screen screen, IntPtr ximage)
{
int width, height;
Xlib.XSharpGetImageSize(ximage, out width, out height);
Bitmap bitmap = new Bitmap(screen, width, height);
Graphics graphics = new Graphics(bitmap);
graphics.PutXImage(ximage, 0, 0, 0, 0, width, height);
graphics.Dispose();
return bitmap;
}
// Redraw this button.
private void Draw()
{
using(Graphics graphics = new Graphics(this))
{
OnPaint(graphics);
}
}
// Draw a caption button. Returns the width of the button.
private static int DrawCaptionButton
(Graphics graphics, Rectangle rect,
int subtract, bool pressed, bool draw,
XPixmap buttonPixmap)
{
int buttonSize = rect.height - 4;
int x = rect.x + rect.width - subtract - buttonSize;
int y = rect.y + 2;
if(draw)
{
if(pressed)
{
graphics.DrawEffect(x, y, buttonSize, buttonSize,
Effect.CaptionButtonIndented);
++x;
++y;
}
else
{
graphics.DrawEffect(x, y, buttonSize, buttonSize,
Effect.CaptionButtonRaised);
}
x += (buttonSize - 9) / 2;
y += (buttonSize - 9) / 2;
graphics.DrawBitmap(x, y, 9, 9, buttonPixmap);
}
return buttonSize;
}
/// <summary>
/// <para>Method that is raised when the widget needs to be
/// painted in reponse to an <c>Expose</c> event.</para>
/// </summary>
///
/// <param name="graphics">
/// <para>The graphics object to use to repaint the widget. This
/// graphics object will have been initialised with the widgets foreground
/// and background colors, and with the clipping region set to the area
/// that needs to be repainted.</para>
/// </param>
protected virtual void OnPaint(Graphics graphics)
{
// Nothing to do in this class.
}
/// <summary>
/// <para>Get extent information for this font, when drawing
/// onto a particular graphics context.</para>
/// </summary>
///
/// <param name="graphics">
/// <para>The graphics context to get the extent information for.</para>
/// </param>
///
/// <returns>
/// <para>Returns the extent information.</para>
/// </returns>
///
/// <exception cref="T:System.ArgumentNullException">
/// <para>Raised if <paramref name="graphics"/> is <see langword="null"/>.
/// </para>
/// </exception>
public virtual FontExtents GetFontExtents(Graphics graphics)
{
if(graphics == null)
{
throw new ArgumentNullException("graphics");
}
FontExtents extents = null;
GetFontSet(graphics.dpy, out extents);
return extents;
}
/// <summary>
/// <para>Measure the width, ascent, and descent of a string,
/// to calculate its extents when drawn on a graphics context
/// using this font.</para>
/// </summary>
///
/// <param name="graphics">
/// <para>The graphics context to measure with.</para>
/// </param>
///
/// <param name="str">
/// <para>The string to be measured.</para>
/// </param>
///
/// <param name="index">
/// <para>The starting index in <paramref name="str"/> of the first
/// character to be measured.</para>
/// </param>
///
/// <param name="count">
/// <para>The number of characters <paramref name="str"/>
/// to be measured.</para>
/// </param>
///
/// <param name="width">
/// <para>The width of the string, in pixels.</para>
/// </param>
///
/// <param name="ascent">
/// <para>The ascent of the string, in pixels.</para>
/// </param>
///
/// <param name="descent">
/// <para>The descent of the string, in pixels.</para>
/// </param>
///
/// <exception cref="T:System.ArgumentNullException">
/// <para>Raised if <paramref name="graphics"/> is <see langword="null"/>.
/// </para>
/// </exception>
public virtual void MeasureString
(Graphics graphics, String str, int index, int count,
out int width, out int ascent, out int descent)
{
// Validate the parameters.
if(graphics == null)
{
throw new ArgumentNullException("graphics");
}
if(str == null || count == 0)
{
width = 0;
ascent = 0;
descent = 0;
return;
}
// Extract the substring to be measured.
// TODO: make this more efficient by avoiding the data copy.
str = str.Substring(index, count);
// Get the font set to use to measure the string.
IntPtr fontSet = GetFontSet(graphics.dpy);
if(fontSet == IntPtr.Zero)
{
width = 0;
ascent = 0;
descent = 0;
return;
}
// Get the text extents and decode them into useful values.
XRectangle overall_ink;
XRectangle overall_logical;
try
{
IntPtr display = graphics.dpy.Lock();
Xlib.XSharpTextExtentsSet
(display, fontSet, str,
out overall_ink, out overall_logical);
}
finally
{
graphics.dpy.Unlock();
}
width = overall_logical.width;
ascent = -(overall_logical.y);
descent = overall_logical.height + overall_logical.y;
// Increase the descent to account for underlining.
// We always draw the underline on pixel below
// the font base line.
if((style & FontStyle.Underlined) != 0)
{
if(descent < 2)
{
descent = 2;
}
}
}
// Clear a double buffer at the start of a drawing operation.
internal void ClearAtStart(Graphics graphics)
{
// Fill the pixmap with the background color if necessary.
// We don't have to do this with Xdbe buffers because the
// X server should have already taken care of it for us
// during the last expose operation on the widget.
// [Marc Haisenko] I'm experiencing a strange bug if double
// buffering is enabled and certain widgets use a transparent
// background color... this is fixed by clearing the buffer.
// But I don't think this is the cause...
if ((!usesXdbe) || (widget.Background.Index == StandardColor.Inherit))
{
graphics.Clear();
}
}
// End a double buffer drawing operation.
internal void End(Graphics graphics)
{
try
{
IntPtr display = dpy.Lock();
if(handle != XDrawable.Zero)
{
if(usesXdbe)
{
Xlib.XdbeSwapInfo info = new Xlib.XdbeSwapInfo();
info.swap_window = widget.GetWidgetHandle();
info.swap_action = Xlib.XdbeSwapAction.Background;
Xlib.XdbeSwapBuffers(display, ref info, 1);
}
else
{
using(Graphics g = new Graphics(widget))
{
Xlib.XCopyArea
(display, handle,
widget.GetGCHandle(), g.gc, 0, 0,
(uint)width, (uint)height, 0, 0);
}
}
}
}
finally
{
dpy.Unlock();
}
}
// Change the state of a caption button. Returns true if the
// button was pressed before we changed its state.
private bool ChangeButtonState(HitTest hitTest, bool pressed)
{
// Determine what change we need to apply.
CaptionFlags buttonsToDraw = (CaptionFlags)0;
CaptionFlags pressedState = (CaptionFlags)0;
CaptionFlags origFlags = flags;
switch(hitTest)
{
case HitTest.Close:
{
buttonsToDraw = CaptionFlags.HasClose;
pressedState = CaptionFlags.ClosePressed;
}
break;
case HitTest.Maximize:
{
buttonsToDraw = CaptionFlags.HasMaximize;
pressedState = CaptionFlags.MaximizePressed;
}
break;
case HitTest.Minimize:
{
buttonsToDraw = CaptionFlags.HasMinimize;
pressedState = CaptionFlags.MinimizePressed;
}
break;
case HitTest.Restore:
{
buttonsToDraw = CaptionFlags.HasRestore;
pressedState = CaptionFlags.RestorePressed;
}
break;
case HitTest.Help:
{
buttonsToDraw = CaptionFlags.HasHelp;
pressedState = CaptionFlags.HelpPressed;
}
break;
}
if(pressed)
{
flags |= pressedState;
}
else
{
flags &= ~pressedState;
}
// Redraw the caption buttons to match the state change.
if(flags != origFlags)
{
Rectangle rect = new Rectangle
(FrameBorderSize, FrameBorderSize,
width - FrameBorderSize * 2,
captionHeight - FrameBorderSize);
using(Graphics graphics = new Graphics(this))
{
DrawCaptionButtons
(graphics, rect, flags, buttonsToDraw);
}
}
return ((origFlags & pressedState) != 0);
}
// Paint this widget in response to an "Expose" event.
protected override void OnPaint(Graphics graphics)
{
// Draw the thick 3D border around the outside first.
graphics.DrawEffect(0, 0, width, height, Effect.Raised);
// Get the rectangle containing the caption area.
Rectangle rect = new Rectangle
(FrameBorderSize, FrameBorderSize,
width - FrameBorderSize * 2,
captionHeight - FrameBorderSize);
// If the rectangle does not overlap the expose region,
// then there is no point drawing the main caption area.
if(!graphics.ExposeRegion.Overlaps(rect))
{
return;
}
// Get the colors to use for the foreground and background.
Color foreground, background, endBackground;
if((flags & CaptionFlags.Active) != 0)
{
foreground = new Color(StandardColor.HighlightForeground);
background = new Color(StandardColor.HighlightBackground);
endBackground =
new Color(StandardColor.HighlightEndBackground);
}
else
{
foreground = new Color(StandardColor.Background);
background = new Color(StandardColor.BottomShadow);
endBackground = new Color(StandardColor.EndBackground);
}
// Create a gradient for the title bar, if necessary.
if(gradient != null &&
(gradient.Width != rect.width ||
gradient.Height != rect.height))
{
// The size has changed and we need a new gradient.
gradient.Dispose();
gradient = null;
}
if(gradient == null && screen.DefaultDepth >= 15)
{
DotGNU.Images.Image image = CreateGradient
(rect.width, rect.height, background, endBackground);
gradient = new Xsharp.Image(screen, image.GetFrame(0));
image.Dispose();
}
// Clear the caption background.
if(gradient == null)
{
graphics.Foreground = background;
graphics.SetFillSolid();
graphics.FillRectangle(rect);
}
else
{
graphics.SetFillTiled(gradient.Pixmap, rect.x, rect.y);
graphics.FillRectangle(rect);
graphics.SetFillSolid();
}
// Draw the caption buttons and then subtract that
// region off the caption rectangle so we don't get
// bleed through when we draw the caption text.
rect.width -= DrawCaptionButtons
(graphics, rect, flags, (CaptionFlags)(~0));
// Bail out if the rectangle is too small for the text.
if(rect.width <= 2)
{
return;
}
// Position the caption text.
Font font = GetCaptionFont();
FontExtents extents = font.GetFontExtents(graphics);
int textY = (rect.height - extents.Ascent) / 2;
textY += rect.y + extents.Ascent;
// Draw the caption text, clipped to the caption area
// so that it won't overwrite the buttons on the right.
using(Region region = new Region(graphics.ExposeRegion))
{
region.Intersect(rect);
graphics.SetClipRegion(region);
graphics.Foreground = foreground;
graphics.DrawString(rect.x + 2, textY, child.Name, font);
}
}
// Draw the caption buttons in their current state. Returns the
// number of pixels on the right of the caption that are occupied
// by the buttons.
private static int DrawCaptionButtons
(Graphics graphics, Rectangle rect,
CaptionFlags flags, CaptionFlags buttonsToDraw)
{
int subtract = 2;
if((flags & CaptionFlags.HasClose) != 0)
{
subtract += DrawCaptionButton
(graphics, rect, subtract,
((flags & CaptionFlags.ClosePressed) != 0),
((buttonsToDraw & CaptionFlags.HasClose) != 0),
graphics.dpy.bitmaps.Close);
if((flags & (CaptionFlags.HasMaximize |
CaptionFlags.HasRestore |
CaptionFlags.HasMinimize)) != 0)
{
// Leave a gap between the close button and the others.
subtract += 2;
}
}
if((flags & CaptionFlags.HasMaximize) != 0)
{
subtract += DrawCaptionButton
(graphics, rect, subtract,
((flags & CaptionFlags.MaximizePressed) != 0),
((buttonsToDraw & CaptionFlags.HasMaximize) != 0),
graphics.dpy.bitmaps.Maximize);
}
if((flags & CaptionFlags.HasRestore) != 0)
{
subtract += DrawCaptionButton
(graphics, rect, subtract,
((flags & CaptionFlags.RestorePressed) != 0),
((buttonsToDraw & CaptionFlags.HasRestore) != 0),
graphics.dpy.bitmaps.Restore);
}
if((flags & CaptionFlags.HasMinimize) != 0)
{
subtract += DrawCaptionButton
(graphics, rect, subtract,
((flags & CaptionFlags.MinimizePressed) != 0),
((buttonsToDraw & CaptionFlags.HasMinimize) != 0),
graphics.dpy.bitmaps.Minimize);
}
if((flags & CaptionFlags.HasHelp) != 0)
{
// Leave a gap between the help button and the others.
subtract += 2;
subtract += DrawCaptionButton
(graphics, rect, subtract,
((flags & CaptionFlags.HelpPressed) != 0),
((buttonsToDraw & CaptionFlags.HasHelp) != 0),
graphics.dpy.bitmaps.Help);
}
if(subtract > 2)
{
// Leave a gap between the buttons and the text.
return subtract + 2;
}
else
{
// There are no buttons, so no need for an extra gap.
return 2;
}
}
// Convert an XImage into a Pixmap object.
public static Pixmap XImageToPixmap(Screen screen, IntPtr ximage)
{
int width, height;
Xlib.XSharpGetImageSize(ximage, out width, out height);
Pixmap pixmap = new Pixmap(screen, width, height);
Graphics graphics = new Graphics(pixmap);
graphics.PutXImage(ximage, 0, 0, 0, 0, width, height);
graphics.Dispose();
return pixmap;
}
public override void DrawString
(Graphics graphics, int x, int y,
String str, int index, int count)
{
// Validate the parameters.
if(x < -32768 || x > 32767 || y < -32768 || y > 32767)
{
throw new XException(S._("X_PointCoordRange"));
}
if(graphics == null)
{
throw new ArgumentNullException("graphics");
}
if(str == null || count <= 0)
{
return;
}
if(index < 0 || index >= str.Length ||
count > (str.Length - index))
{
return;
}
// Get the font set to use for the font.
IntPtr fontSet = GetFontSet(graphics.dpy);
if(fontSet == IntPtr.Zero)
{
return;
}
// Draw the string using the specified font set.
try
{
IntPtr display = graphics.dpy.Lock();
Xlib.XSharpDrawStringPCF
(display, graphics.drawableHandle, graphics.gc,
fontSet, x, y, str, index, count,
(int)style);
}
finally
{
graphics.dpy.Unlock();
}
}
// Select this pen into a graphics object.
public override void Select(IToolkitGraphics _graphics)
{
if (_graphics == null)
{
return;
}
if (_graphics is DrawingGraphics)
{
DrawingGraphics graphics = _graphics as DrawingGraphics;
Xsharp.Graphics g = graphics.graphics;
int width = (int)(properties.Width);
LineStyle style = MapLineStyle(properties.DashStyle);
if (style == LineStyle.LineOnOffDash)
{
if (width == 1)
{
width = 0;
}
switch (properties.DashStyle)
{
case DashStyle.Dash:
{
g.DashPattern = dash;
}
break;
case DashStyle.Dot:
{
g.DashPattern = dot;
}
break;
case DashStyle.DashDot:
{
g.DashPattern = dashdot;
}
break;
case DashStyle.DashDotDot:
{
g.DashPattern = dashdotdot;
}
break;
case DashStyle.Custom:
{
float [] src = properties.DashPattern;
int iLen = src.Length;
byte [] ayCopy = new byte[iLen];
float fWidth = properties.Width;
float tmp;
for (int i = 0; i < iLen; i++)
{
tmp = src[i] * fWidth;
if (tmp < 0)
{
tmp = 0;
}
else if (tmp > 0xFF)
{
tmp = 0xFF;
}
ayCopy[i] = (byte)(tmp);
if (ayCopy[i] == 0)
{
ayCopy[i] = 1; // must not be zero
}
}
g.DashPattern = ayCopy;
}
break;
}
}
g.Function = GCFunction.GXcopy;
g.SubwindowMode = SubwindowMode.ClipByChildren;
g.LineWidth = width;
g.LineStyle = style;
g.CapStyle = MapCapStyle(properties.EndCap);
g.JoinStyle = MapJoinStyle(properties.LineJoin);
g.Foreground = DrawingToolkit.DrawingToXColor
(properties.Color);
g.SetFillSolid();
graphics.Pen = this;
}
else if (_graphics is DrawingGraphicsImage)
{
DrawingGraphicsImage graphics = _graphics as DrawingGraphicsImage;
graphics.Pen = this;
}
}
/// <summary>
/// <para>Draw a string at a particular position on a
/// specified graphics context.</para>
/// </summary>
///
/// <param name="graphics">
/// <para>The graphics context to draw on.</para>
/// </param>
///
/// <param name="x">
/// <para>The X co-ordinate of the position to start drawing text.</para>
/// </param>
///
/// <param name="y">
/// <para>The Y co-ordinate of the position to start drawing text.</para>
/// </param>
///
/// <param name="str">
/// <para>The string to be drawn.</para>
/// </param>
///
/// <param name="index">
/// <para>The starting index in <paramref name="str"/> of the first
/// character to be measured.</para>
/// </param>
///
/// <param name="count">
/// <para>The number of characters <paramref name="str"/>
/// to be measured.</para>
/// </param>
///
/// <exception cref="T:Xsharp.XException">
/// <para>One of the co-ordinate values is out of range.</para>
/// </exception>
///
/// <exception cref="T:System.ArgumentNullException">
/// <para>Raised if <paramref name="graphics"/> is <see langword="null"/>.
/// </para>
/// </exception>
public virtual void DrawString
(Graphics graphics, int x, int y,
String str, int index, int count)
{
// Validate the parameters.
if(x < -32768 || x > 32767 || y < -32768 || y > 32767)
{
throw new XException(S._("X_PointCoordRange"));
}
if(graphics == null)
{
throw new ArgumentNullException("graphics");
}
if(str == null || count == 0)
{
return;
}
// Extract the substring to be measured.
// TODO: make this more efficient by avoiding the data copy.
str = str.Substring(index, count);
// Get the font set to use for the font.
IntPtr fontSet = GetFontSet(graphics.dpy);
if(fontSet == IntPtr.Zero)
{
return;
}
// Draw the string using the specified font set.
try
{
IntPtr display = graphics.dpy.Lock();
Xlib.XSharpDrawStringSet
(display, graphics.drawableHandle, graphics.gc,
fontSet, x, y, str, (int)style);
}
finally
{
graphics.dpy.Unlock();
}
}
// Start a double buffer drawing operation.
internal void Start(Graphics graphics)
{
// Re-create the pixmap object if the widget size has changed.
if(!usesXdbe)
{
if(widget.width != width || widget.height != height)
{
try
{
IntPtr display = dpy.Lock();
if(handle != XDrawable.Zero)
{
Xlib.XFreePixmap(display, (XPixmap)handle);
}
handle = (XDrawable)
Xlib.XCreatePixmap
(display, (XDrawable)
Xlib.XRootWindowOfScreen(screen.screen),
(uint)(widget.Width),
(uint)(widget.Height),
(uint)Xlib.XDefaultDepthOfScreen
(screen.screen));
}
finally
{
dpy.Unlock();
}
}
}
// Copy the width and height values from the widget.
width = widget.Width;
height = widget.Height;
}
/// <summary>
/// <para>Update this widget by immediately redrawing invalidated
/// regions.</para>
/// </summary>
///
/// <param name="clear">
/// <para>Setting clear to true clears the region to the background.
/// </para>
/// </param>
public void Update(bool clear)
{
Region region = invalidateRegion;
invalidateRegion = null;
if(region != null)
{
// Remove the region from the pending list.
dpy.RemovePendingInvalidate(this);
// No point redrawing if we are unmapped or the
// region to be drawn is empty.
if(mapped && AncestorsMapped && (!clear ||
ClearRegion(region, XBool.False)))
{
// Paint the region as if we got a regular expose.
Graphics graphics = new Graphics(this);
graphics.exposeRegion = region;
graphics.SetClipRegion(region);
try
{
OnPaint(graphics);
}
finally
{
graphics.Dispose();
}
}
// Dispose the region that we no longer require.
region.Dispose();
}
}
// Paint this widget in response to an "Expose" event.
protected override void OnPaint(Graphics graphics)
{
XPixmap pixmap;
if((flags & CaptionWidget.CaptionFlags.HasClose) != 0)
{
pixmap = graphics.dpy.bitmaps.Close;
}
else if((flags & CaptionWidget.CaptionFlags.HasRestore)
!= 0)
{
pixmap = graphics.dpy.bitmaps.Restore;
}
else
{
pixmap = graphics.dpy.bitmaps.Minimize;
}
int x = (width - 9) / 2;
int y = (height - 9) / 2;
if(pressed && entered)
{
graphics.DrawEffect(0, 0, width, height,
Effect.CaptionButtonIndented);
++x;
++y;
}
else
{
graphics.DrawEffect(0, 0, width, height,
Effect.CaptionButtonRaised);
}
graphics.DrawBitmap(x, y, 9, 9, pixmap);
}
// Process pending exposures on this widget.
internal void Expose()
{
Region region = exposeRegion;
if(region != null)
{
exposeRegion = null;
// sometimes it could be that Expose is called but the handle is destroyed.
// so check here, if handle not null.
if( handle != XDrawable.Zero ) {
try {
Graphics graphics = new Graphics(this);
graphics.exposeRegion = region;
graphics.SetClipRegion(region);
OnPaint(graphics);
graphics.Dispose();
region.Dispose();
}
catch( XInvalidOperationException ) { // irgnore Widget disposed exception
}
}
}
}
// Get the size of the top-most border on a caption widget,
// including the title bar display area.
private static int GetCaptionHeight(Widget widget)
{
Font font = GetCaptionFont();
int height;
using(Graphics graphics = new Graphics(widget))
{
FontExtents extents = font.GetFontExtents(graphics);
height = extents.Ascent + extents.Descent;
}
height += CaptionExtra;
if(height < CaptionMinimum)
{
height = CaptionMinimum;
}
return height + FrameBorderSize;
}