Develop Reference

How to use AddArc() method in C#

I have this little code to use AddArc() method in a label, but when I execute the code the label disappears. I believe it is the numbers I have used, I followed instructions from the Windows documentation and it had these parameters there too.
GraphicsPath gp = new GraphicsPath();
Rectangle rec = new Rectangle(20, 20, 50, 100);
gp.AddArc(rec, 0 , 180);
label2.Region = new Region(gp);
label2.Invalidate();
I used another code to make the correct way or curve in a text
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
var center = new Point(Width / 2, Height / 2);
var radius = Math.Min(Width, Height) / 3;
var text = "Hello";//txtUp.Text;
var font = new Font(FontFamily.GenericSansSerif, 24, FontStyle.Bold);
for (var i = 0; i < text.Length; ++i)
{
var c = new String(text[i], 1);
var size = e.Graphics.MeasureString(c, font);
var charRadius = radius + size.Height;
var angle = (((float)i / text.Length) - 2);
var x = (int)(center.X + Math.Cos(angle) * charRadius);
var y = (int)(center.Y + Math.Sin(angle) * charRadius);
e.Graphics.TranslateTransform(x, y);
e.Graphics.RotateTransform((float)(90 + 360 * angle / (2 * Math.PI)));
e.Graphics.DrawString(c, font, Brushes.Red, 0, 0);
e.Graphics.ResetTransform();
e.Graphics.DrawArc(new Pen(Brushes.Transparent, 2.0f), center.X - radius, center.Y - radius, radius * 2, radius * 2, 0, 360);
}
}
but it wont show in front of a panel is it possible.
This is what it looks like:
Is it possible to move that text in front of the green circle?

Calculating text width for DXF

I am using netDXF (https://netdxf.codeplex.com/) to generate a DXF file for use with AutoCAD. However, I have an issue with getting the width of MText correct. I want to be able to define a width that the text should fit into, and change the width factor of the text (squash it horizontally) so that it fits in the defined area. So if I have a 40mm width to fit the text into and the text is 80mm long, it needs to have a width factor of 0.5. The only problem is that I don't know how to accurately determine the width of the text. I have tried the following methods and was unsuccessful in getting the correct result:
Why is Graphics.MeasureString() returning a higher than expected number?
Measure a String without using a Graphics object?
http://www.codeproject.com/Articles/2118/Bypass-Graphics-MeasureString-limitations
I have attached my code. I am basically printing a horizontal line using each of the 3 methods to calculate text width and comparing it to the actual text width. If I change the font, I get varying results. I have attached two images. One using the code with Calibri and one with Arial. I need the line to be on the edges of the text no matter what font I use.
Here is my code:
public void TestMethod1()
{
Application.SetCompatibleTextRenderingDefault(false);
//text width in mm
float textWidth = 40;
float textHeight = 200;
string labelText = "HELLO WORLD!";
TextStyle textStyle = new TextStyle("Calibri");
DxfDocument dxf = new DxfDocument();
Layer layer1 = new Layer("layer1");
layer1.Color = new AciColor(0, 0, 255);
layer1.Name = "Text";
MText text1 = new MText(new Vector2(0, 0), textHeight, 0, textStyle);
text1.Layer = layer1;
text1.AttachmentPoint = MTextAttachmentPoint.MiddleCenter;
//Will the text fit in the bounds of the rectangle? If not change width factor so it does.
Font f = new Font(textStyle.FontName, textHeight);
Size size = TextRenderer.MeasureText(labelText, f);
SizeF sizeF = graphicsMeasureString(labelText, f);
int width = MeasureDisplayStringWidth(labelText, f);
float widthFactor = Math.Min(1, textWidth / sizeF.Width);
MTextFormattingOptions mtextOptions = new MTextFormattingOptions(text1.Style);
//mtextOptions.WidthFactor = widthFactor;
text1.Write(labelText, mtextOptions);
//Red, g.MeasureString
Line line1 = new Line(new Vector2(0 - sizeF.Width / 2, 0), new Vector2(0 + sizeF.Width / 2, 0));
line1.Color = new AciColor(255, 0, 0);
//Green, TextRenderer
Line line2 = new Line(new Vector2(0 - size.Width / 2, 5), new Vector2(0 + size.Width / 2, 5));
line2.Color = new AciColor(0, 255, 0);
//Yellow, MeasureDisplayStringWidth
Line line3 = new Line(new Vector2(0 - width / 2, -5), new Vector2(0 + width / 2, -5));
line3.Color = new AciColor(255, 255, 0);
dxf.AddEntity(text1);
dxf.AddEntity(line1);
dxf.AddEntity(line2);
dxf.AddEntity(line3);
dxf.Save("Text Width Test.dxf");
}
public SizeF graphicsMeasureString(string text, Font f)
{
Bitmap fakeImage = new Bitmap(1, 1);
Graphics g = Graphics.FromImage(fakeImage);
SizeF sizeF = g.MeasureString(text, f, new PointF(100, 0), StringFormat.GenericTypographic);
return sizeF;
}
public int MeasureDisplayStringWidth(string text, Font f)
{
Size size = TextRenderer.MeasureText(text, f);
Bitmap fakeImage = new Bitmap(1, 1);
Graphics g = Graphics.FromImage(fakeImage);
System.Drawing.StringFormat format = new System.Drawing.StringFormat();
System.Drawing.RectangleF rect = new System.Drawing.RectangleF(0, 0, 1000, 1000);
System.Drawing.CharacterRange[] ranges = { new System.Drawing.CharacterRange(0, text.Length) };
System.Drawing.Region[] regions = new System.Drawing.Region[1];
format.SetMeasurableCharacterRanges(ranges);
regions = g.MeasureCharacterRanges(text, f, rect, format);
rect = regions[0].GetBounds(g);
return (int)(rect.Right + 1.0f);
}

Ownerdrawn TreeView (WinForms)

I have a TreeView control with checkboxes which is completely owner drawn (DrawMode = TreeViewDrawMode.OwnerDrawAll).
What I'm trying to do is to have the checkboxes owner drawn, so that they can have a grayed state. I'm using VisualStyleRenderer for this.
The problem arises when I have to correctly place the expand/collapse glyph and the checkbox in the item bounds, because the "hit-test areas" for both the glyph and the checkbox seems to be unknown and unchangeable.
Is there a way to get the bounds of those areas, or to replace the default ones with custom values?

I ran into the same problem. You have to offset your drawing by the proper amount, which is predictable.
There's probably more here than you need, but here's my drawing for a custom tree I used alongside a calendar control:
private void TreeViewControl_DrawNode(Object sender, DrawTreeNodeEventArgs e)
{
//What might seem like strange positioning/offset is to ensure that our custom drawing falls in
// line with where the base drawing would appear. Otherwise, click handlers (hit tests) fail
// to register properly if our custom-drawn checkbox doesn't fall within the expected coordinates.
Int32 boxSize = 16;
Int32 offset = e.Node.Parent == null ? 3 : 21;
Rectangle bounds = new Rectangle(new Point(e.Bounds.X + offset, e.Bounds.Y + 1), new Size(boxSize, boxSize));
ControlPaint.DrawCheckBox(e.Graphics, bounds, e.Node.Checked ? ButtonState.Checked : ButtonState.Normal);
if (e.Node.Parent != null)
{
Color c = Color.Black;
String typeName = e.Node.Name.Remove(0, 4);
Object o = Enum.Parse(typeof(CalendarDataProvider.CalendarDataItemType), typeName);
if (o != null && (o is CalendarDataProvider.CalendarDataItemType))
c = CalendarDataProvider.GetItemTypeColor((CalendarDataProvider.CalendarDataItemType)o);
bounds = new Rectangle(new Point(bounds.X + boxSize + 2, e.Bounds.Y + 1), new Size(13, 13));
using (SolidBrush b = new SolidBrush(c))
e.Graphics.FillRectangle(b, bounds);
e.Graphics.DrawRectangle(Pens.Black, bounds);
e.Graphics.DrawLine(Pens.Black, new Point(bounds.X + 1, bounds.Bottom + 1), new Point(bounds.Right + 1, bounds.Bottom + 1));
e.Graphics.DrawLine(Pens.Black, new Point(bounds.Right + 1, bounds.Y + 1), new Point(bounds.Right + 1, bounds.Bottom + 1));
}
Font font = new Font("Microsoft Sans Serif", 9f, e.Node.Parent == null ? FontStyle.Bold : FontStyle.Regular);
bounds = new Rectangle(new Point(bounds.X + boxSize + 2, e.Bounds.Y), new Size(e.Bounds.Width - offset - 2, boxSize));
e.Graphics.DrawString(e.Node.Text, font, Brushes.Black, bounds);
}

How to create a form in shape of rhomb?

How to create a form in shape of rhomb?
I managed to create a shape in form of ellipse with the help of this:
private void Form1_Load(object sender, EventArgs e)
{
System.Drawing.Drawing2D.GraphicsPath myPath = new System.Drawing.Drawing2D.GraphicsPath();
myPath.AddEllipse(45, 60, 200, 200);
Region myRegion = new Region(myPath);
this.Region = myRegion;
}
How can I do it but making rhomb?

Use myPath.AddLines instead of the myPath.AddEllipse:
private void Form1_Load(object sender, EventArgs e)
{
using (GraphicsPath myPath = new GraphicsPath())
{
myPath.AddLines(new[]
{
new Point(0, Height / 2),
new Point(Width / 2, 0),
new Point(Width, Height / 2),
new Point(Width / 2, Height)
});
Region = new Region(myPath);
}
}

Above answer by #Dmitry helped me a lot. However, it does not draw a complete rhombus, as claimed. The last segment is not drawn due to absent final point, which must coincide with the starting point. Line array should contain five points, not four.
I have made some corrections and come up with this function, which draws a rhombus withing a given rectangle:
private void DrawRhombus(Graphics graphics, Rectangle rectangle)
{
using (GraphicsPath myPath = new GraphicsPath())
{
myPath.AddLines(new[]
{
new Point(rectangle.X, rectangle.Y + (rectangle.Height / 2)),
new Point(rectangle.X + (rectangle.Width / 2), rectangle.Y),
new Point(rectangle.X + rectangle.Width, rectangle.Y + (rectangle.Height / 2)),
new Point(rectangle.X + (rectangle.Width / 2), rectangle.Y + rectangle.Height),
new Point(rectangle.X, rectangle.Y + (rectangle.Height / 2))
});
using (Pen pen = new Pen(Color.Black, 1))
graphics.DrawPath(pen, myPath);
}
}

Animated bar in progress bar winform

I'm writing an extended progress bar control at present, 100% open source and I've created some basic styles with gradients and solid colours.
One of the options I wanted to add was animation to the bar, prety much like the windows 7 and vista green progress bar. So I need to add a moving "Glow" to the % bar, however my attempt at this looks terrible.
My method is to draw an ellipse with set size and move it's x position until it reaches the end were the animation starts again.
First of does anyone have nay links or code to help me achieve the current windows 7 glow effect using GDI or some similar method?
I have several other animations that will also be added the the bar hence the GDI.
private void renderAnimation(PaintEventArgs e)
{
if (this.AnimType == animoptions.Halo)
{
Rectangle rec = e.ClipRectangle;
Rectangle glow = new Rectangle();
//SolidBrush brush = new SolidBrush(Color.FromArgb(100, Color.White));
//int offset = (int)(rec.Width * ((double)Value / Maximum)) - 4;
int offset = (int)(rec.Width / Maximum) * Value;
if (this.animxoffset > offset)
{
this.animxoffset = 0;
}
glow.Height = rec.Height - 4;
if (this.animxoffset + glow.X > offset)
{
glow.Width = offset - (this.animxoffset + 50);
}
else
{
glow.Width = 50;
}
glow.X = this.animxoffset;
LinearGradientBrush brush = new LinearGradientBrush(glow, Color.FromArgb(0, Color.White), Color.FromArgb(100, Color.White), LinearGradientMode.Horizontal);
e.Graphics.FillEllipse(brush, this.animxoffset, 2, glow.Width, glow.Height);
brush.Dispose();
string temp = offset.ToString();
e.Graphics.DrawString(temp + " : " + glow.X.ToString(), DefaultFont, Brushes.Black, 2, 2);
animTimer = new System.Timers.Timer();
animTimer.Interval = 10;
animTimer.Elapsed += new System.Timers.ElapsedEventHandler(t_Elapsed);
animTimer.Start();
}
}
void t_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
this.animTimer.Stop();
this.animxoffset += 2;
Invalidate();
}

This is just an example glow iterating through a pen array.
You could also use a transparent image (although it could have a performance impact).
Pen[] gradient = { new Pen(Color.FromArgb(255, 200, 200, 255)), new Pen(Color.FromArgb(150, 200, 200, 255)), new Pen(Color.FromArgb(100, 200, 200, 255)) };
int x = 20;
int y = 20;
int sizex = 200;
int sizey = 10;
int value = 25;
//draw progress bar basic outline (position - 1 to compensate for the outline)
e.Graphics.DrawRectangle(Pens.Black, new Rectangle(x-1, y-1, sizex, sizey));
//draw the percentage done
e.Graphics.FillRectangle(Brushes.AliceBlue, new Rectangle(x, y, (sizex/100)*value, sizey));
//to add the glow effect just add lines around the area you want to glow.
for (int i = 0; i < gradient.Length; i++)
{
e.Graphics.DrawRectangle(gradient[i], new Rectangle(x - (i + 1), y - (i + 1), (sizex / 100) * value + (2 * i), sizey + (2 * i)));
}