I am trying to draw a circle within my form.
But it is strange to me I set form width and height to a fixed number, i do the same for the circle, but the circle figure goes outside the form.
private void Form3_Paint(object sender, PaintEventArgs e)
{
this.SuspendLayout();
gr = this.CreateGraphics();
gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
Brush fill_circ3 = Brushes.Blue;
Pen ellipse_pen = new Pen(Color.Blue);
ellipse_pen.Width = (float)2.0;
this.Width = this.Height = 400;
Rectangle rect = new Rectangle(0, 0, this.Width, this.Height);
gr.DrawEllipse(ellipse_pen, rect);
this.ResumeLayout();
}
The 3rd and 4th parameters of the Rectangle constructor defines the size in width and height of the circle.
See the circle I got
Why does the circle goes outside the form???! I have set form and circle sizes the same!!!
It's because you use the Window size, not the "client" size. Just replace your code by this:
gr.DrawEllipse(ellipse_pen, this.ClientRectangle);
The client area of a control is the bounds of the control, minus the
nonclient elements such as scroll bars, borders, title bars, and
menus.
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
DrawLetter();
if (counter == 0)
{
t.Stop();
TakeScreenShot();
}
}
private void DrawLetter()
{
var letter = counter.ToString();
Graphics g = Graphics.FromHdc(GetDC(IntPtr.Zero));
float width = ((float)this.ClientRectangle.Width);
float height = ((float)this.ClientRectangle.Width);
float emSize = height;
Font font = new Font(FontFamily.GenericSansSerif, emSize, FontStyle.Regular);
font = FindBestFitFont(g, letter.ToString(), font, this.ClientRectangle.Size);
SizeF size = g.MeasureString(letter.ToString(), font);
g.DrawString(letter, font, new SolidBrush(Color.White), (width - size.Width) / 2, 0);
}
private Font FindBestFitFont(Graphics g, String text, Font font, Size proposedSize)
{
// Compute actual size, shrink if needed
while (true)
{
SizeF size = g.MeasureString(text, font);
// It fits, back out
if (size.Height <= proposedSize.Height &&
size.Width <= proposedSize.Width) { return font; }
// Try a smaller font (90% of old size)
Font oldFont = font;
font = new Font(font.Name, (float)(font.Size * .9), font.Style);
oldFont.Dispose();
}
}
void TakeScreenShot()
{
bmpScreenshot = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
gfxScreenshot = Graphics.FromImage(bmpScreenshot);
gfxScreenshot.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);
bmpScreenshot.Save(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) + #"\ScreenCaptures\newfile.png", ImageFormat.Png);
}
I am able to draw the string but it is writing on top of itself.
How can I clear it? Basically I want the countdown to appear on the screen then take a screenshot.
Right now the number is overwritten by another.
You can do the following: create an additional transparent form, and it will display timer values. This will allow you to erase the previous value. In addition, this will allow to get rid of the function call GetDC via PInvoke.
Form timerForm; // main form field
// Create and show additional transparent form before starting the timer
timerForm = new Form
{
FormBorderStyle = FormBorderStyle.None,
WindowState = FormWindowState.Maximized,
TransparencyKey = SystemColors.Control,
ShowInTaskbar = false
};
timerForm.Show();
timer.Start();
Change the method DrawLetter as follows
private void DrawLetter()
{
var letter = counter.ToString();
Graphics g = timerForm.CreateGraphics();
float width = ClientRectangle.Width;
float height = ClientRectangle.Width;
float emSize = height;
using (Font font1 = new Font(FontFamily.GenericSansSerif, emSize, FontStyle.Regular))
using (Font font2 = FindBestFitFont(g, letter, font1, ClientRectangle.Size))
using (var brush = new SolidBrush(Color.White))
{
SizeF size = g.MeasureString(letter, font2);
g.Clear(SystemColors.Control);
g.DrawString(letter, font2, brush, (width - size.Width) / 2, 0);
}
}
We must release all used resources like fonts and brushes. For this I applied using.
Change the timer tick event handler as follows
private void timer1_Tick(object sender, EventArgs e)
{
counter--;
DrawLetter();
if (counter == 0)
{
timer.Stop();
TakeScreenShot();
timerForm.Dispose(); // must release
}
}
FindBestFitFont and TakeScreenShot methods remain unchanged.
Draw your font to a different bitmap. Transparent background (or whatever doesn't invert, see below - perhaps black).
(now you could also draw it with a different colored shadow to mitigate drawing on similar colored background - but the natures of SRCINVERT/XOR, below, will mitigate this as well)
Use BitBlt to copy it to the screen
Use the SRCINVERT raster op.
(note: the colors may be different as it is XORing it with pixels underneath)
Now when is is time to erase, just make the same bitblt with the same contents as previous, the double XOR effect caused by SRCINVERT will have the effect of erasing it.
Then draw the next font.
Note: if desktop is updated between calls, all bets are off.
better...
Rather than attempting a transparent background, draw it on a white background. This will eliminate contrast issues with the font, eliminate concern with dynamic updates, and eliminate problems with erasing. Sometimes you have to admit - the method & code isn't the problem, the requirements are the problem. This all depends of course on the source of the requirements, etc.
If it needs to look professional, don't put the content on the screen, draw it after you take the screen capture.
If you end up using the transparent window approach, the screen shot may miss the transparent window. To get it, see this question:
Capture screenshot Including Semitransparent windows in .NET. (could be fixed by newer .net / newer windows versions)
You need to invalidate all the windows on the desktop by using the InvalidateRect function to erase the previously drawn letter.
See additional codes below for the DrawLetter method.
[DllImport("user32")]
private static extern bool InvalidateRect(IntPtr hwnd, IntPtr rect, bool bErase);
private void DrawLetter()
{
var letter = counter.ToString();
Graphics g = Graphics.FromHdc(GetDC(IntPtr.Zero));
float width = ((float)this.ClientRectangle.Width);
float height = ((float)this.ClientRectangle.Width);
float emSize = height;
Font font = new Font(FontFamily.GenericSansSerif, emSize, FontStyle.Regular);
font = FindBestFitFont(g, letter.ToString(), font, this.ClientRectangle.Size);
SizeF size = g.MeasureString(letter.ToString(), font);
// Invalidate all the windows.
InvalidateRect(IntPtr.Zero, IntPtr.Zero, true);
// Sometimes, the letter is drawn before the windows are invalidated.
// To fix that, add a small delay before drawing the letter.
System.Threading.Thread.Sleep(100);
// Finally, draw the letter.
g.DrawString(letter, font, new SolidBrush(Color.White), (width - size.Width) / 2, 0);
}
A solution is:
You must take a snapshot of that area you want to show counter before all things. Then call DrawImage function to draw snapshot image before call DrawString function every time.
I have this code
Graphics g;
g.FillRectangle(new SolidBrush(Color.Red), _Location.X - 2, _Location.Y - 2, 10, 10);
and the rectangle is shot at an angle to some direction, how can I get the rectangle to rotate while moving or rotate at all.
This should rotate a rectangle moving across the screen.
private int _angle = 0;
private Point _location = new Point(0, 0);
private void _timer_Tick(object sender, System.EventArgs e)
{
// nothing interesting here, moving the top left co-ordinate of the
// rectangle at constant rate
_location = new System.Drawing.Point(_location.X + 2, _location.Y + 2);
_angle += 5; // our current rotation angle
this.Invalidate();
}
void Form1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
// rebase the co-ordinate system so our current x,y is 0, 0 and that is
// the center of the rotation
g.TranslateTransform(_location.X, _location.Y, MatrixOrder.Append);
g.RotateTransform(_angle); // do the rotation
// make sure the centre of the rectangle is the centre of rotation (0, 0)
g.FillRectangle(new SolidBrush(Color.Red), -5, -5, 10, 10);
}
I've figured it out right before I saw #steve16351 's response, but his code was still useful. What I did was switch from using PointF to Rectangle, because the Rectangle has a property which holds the value of the upper left corner's coordinates, so I can increment/decrement that at a stable rate, in my game loop, to make it rotate.
I have a panel on which I draw a radius frame with shadow. But I have a simple frame and a single color. How can I make her to be with smooth tints?
I think you need to use RGB and Alpha channel.
Color BorderColor = Color.FromArgb(((int)(((byte)(161)))), ((int)(((byte)(164)))), ((int)(((byte)(169)))));
private void AfyTextBox_Paint(object sender, PaintEventArgs e)
{
DrawShadow(e);
GraphicsPath path = RoundedRectangle.Create(0, 0, this.Width - 5, this.Height - 5, 3);
e.Graphics.DrawPath(new Pen(BorderColor), path);
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Brushes.Black, 1);
e.Graphics.DrawRectangle(p, 3, 3, 89, 30);
}
Why does this code produce a 90px width / 31px height box? i.e one pixel bigger than requested.
BTW: FillRectangle works fine.
I imagine that it is because the command defines the inside size of the rectangle and draws the border around that.