We Keep Coding

How can I scale up the hatchstyle drawn in a rectangle? [closed]

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 7 years ago.
Improve this question
I'm using .Net drawing to draw a diagram. It is essentially a stacked bar chart.
The issue I have is that I want to reduce the amount of lines in the hatch style so in a way scale it up to make it clearer. I've looked around but didn't come across anything that could help me.
I draw a rectangle and then use a hatchbrush to fill it but due to image size the hatchfill becomes less clearer. Thank you for any suggestions.
The hatchStyles and brush types are stored in the db and I use a helper function to return them. So I draw the rectangle and after getting the brush I fill the rectangle. Essentially I want to scale up the hatch fill if that can be done.
g.DrawRectangle(gridpen, startX, startY, BOREHOLE_RECT_WIDTH, layerRectHeight);
brush = GetBoreholeBrush(l.SoilTypeMatrixLevel1Id.PrimaryBrushType,
l.SoilTypeMatrixLevel1Id.PrimaryFillStyle,
l.SoilTypeMatrixLevel1Id.PrimaryColour);
g.FillRectangle(brush, startX, startY, BOREHOLE_RECT_WIDTH, layerRectHeight);
And the getBrush function; the brush type, hatch style and colour are stored in the db and used to create the returned brush:
//===================================
private Brush GetBoreholeBrush(string BrushType, string HatchStyle, string Colour)
//===================================
{
//Decide on what brush type has been chosen.
Brush brush;
if (BrushType.ToLower() == BrushTypes.HatchBrush.ToString().ToLower())
{
brush = new HatchBrush(GetHatchStyle(HatchStyle),
Color.Black, ColorTranslator.FromHtml(Colour));
}
else if (BrushType.ToLower() == BrushTypes.SolidBrush.ToString().ToLower())
{
brush = new HatchBrush(GetHatchStyle(HatchStyle),
Color.Black, ColorTranslator.FromHtml(Colour));
}
else if (BrushType.ToLower() == BrushTypes.TextureBrush.ToString().ToLower())
{
brush = new HatchBrush(GetHatchStyle(HatchStyle),
Color.Black, ColorTranslator.FromHtml(Colour));
}
else
{
brush = new HatchBrush(GetHatchStyle(HatchStyle),
Color.Black, ColorTranslator.FromHtml(Colour));
}
return brush;
}
Function to return the hatch style:
//===================================
private HatchStyle GetHatchStyle(string FillStyle)
//===================================
{
//Loop through each hatch tyle and return the correct one.
foreach (HatchStyle style in Enum.GetValues(typeof(HatchStyle)))
{
if (style.ToString().ToLower() == FillStyle.ToLower())
{
return style;
}
}
return HatchStyle.Vertical;
}
As you can see in the image below the hatch style is not clear.

The most direct but probably not very helpful answer is : No you can't scale the hatch pattern of a HatchBrush.
It is meant to always look sharp at the pixel level and is not even affected by scaling the Graphics object.
Looking at your question I wonder: Are you sure you are really using a HatchBrush? You get the brush from a function GetBoreholeBrush. If you really have stored indices into the 50 HatchStyle then I guess you really use a HatchBrush.
Now as using a HatchBrush won't work I guess you could use a TextureBrush instead..
You could transform the hatch patterns to larger versions by scaling them up; this is not exactly a simple conversion. The direct approach of drawing the larger by an integer factor and without anti-aliasing is simple and may be good enough.
But you may need to fine-tune them, as this way all pixels, that is both line pixels and background pixels get enlarged and also all diagonals will look jagged.
So you would need to balance the hatch size and the stroke width and recreate all patterns you need from scratch in larger sizes.
Here is an example that illustrates the problems with the simple solution; the first row is the original hatch pattern the others are simple texture brush results, scaled by 1x, 2x and 3x..:
First a function to transform a HatchBrush to a TextureBrush
TextureBrush TBrush(HatchBrush HBrush)
{
using (Bitmap bmp = new Bitmap(8,8))
using (Graphics G = Graphics.FromImage(bmp))
{
G.FillRectangle(HBrush, 0, 0, 8, 8);
TextureBrush tb = new TextureBrush(bmp);
return tb;
}
}
Note that the hatch pattern is 8x8 pixels.
Now the Paint code used for the above image:
private void panel1_Paint(object sender, PaintEventArgs e)
{
var hs = (HatchStyle[])Enum.GetValues(typeof(HatchStyle));
for (int i = 0; i < hs.Length; i++)
using (HatchBrush hbr = new HatchBrush(hs[i], Color.GreenYellow))
using (HatchBrush hbr2 = new HatchBrush(hs[i], Color.LightCyan))
{
e.Graphics.FillRectangle(hbr, new Rectangle(i * 20, 10,16,60));
using (TextureBrush tbr = TBrush(hbr2))
{
e.Graphics.FillRectangle(tbr, new Rectangle(i * 20, 80, 16, 60));
tbr.ScaleTransform(2, 2);
e.Graphics.FillRectangle(tbr, new Rectangle(i * 20, 150, 16, 60));
tbr.ResetTransform();
tbr.ScaleTransform(3,3);
e.Graphics.FillRectangle(tbr, new Rectangle(i * 20, 220, 16, 60));
}
}
}
Note that while the TextureBrush has nice methods to modify the texture, the HatchBrush has nothing like that at all..

draw polygon click area

Drawing a polygon according to the input coordinates
i got some code from here, i just take..
void pictureBox1_Paint(object sender, PaintEventArgs e) {
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
List<Point> polyPoints = new List<Point>();
polyPoints.Add(new Point(30, 30));
polyPoints.Add(new Point(36, 105));
polyPoints.Add(new Point(66, 105));
polyPoints.Add(new Point(72, 66));
using (SolidBrush br = new SolidBrush(Color.FromArgb(100, Color.Yellow)))
{
e.Graphics.FillPolygon(br, polyPoints.ToArray());
}
e.Graphics.DrawPolygon(Pens.DarkBlue, polyPoints.ToArray());
}
note : SmoothingMode use header using System.Drawing.Drawing2D
then i got problem about click area, i just want the click area at the visible area, in this case the picturebox1 have size 1366 x 768
this is example of picturebox, i want the red area be clickable and the gray is not clickable area
by default all area in the box is clickable

Have you looked at the Documentation on PictureBox?
I'm looking at it and it seems there's many ways of resizing aspects of the PixtureBox object. Take a look at using the DefaultSize Property or setting the Size property. In either case, you have to wrap the size in a Size object and set the according PictureBox size property.
Such as:
pictureBox1.Size = new Size(xSize, ySize);
or
pictureBox1.DefaultSize = new Size(xSize, ySize);

Drawing in Winforms

I have written this code, however, it doesn't work. Not only will this not work, but none of the methods I have tried for drawing have worked. I've spent more than an hour or two trying to solve this, but to no success. Ive tried simple programs where all it does is display a small line, but it wont work no matter what i do :c
What am I doing wrong, or what could cause this?
private void pictureBox1_MouseDown(object sender,
MouseEventArgs m,
EventArgs e,
PaintEventArgs q)
{
if (m.Button == System.Windows.Forms.MouseButtons.Left)
{
Point currpoint = System.Windows.Forms.Cursor.Position;
Point origin = new Point(0, 0);
decimal sizee = nud.Value;
int size = Convert.ToInt32(sizee);
Random randonGen = new Random();
Color randomColor = Color.FromArgb(randonGen.Next(255),
randonGen.Next(255),
randonGen.Next(255));
Pen selPen = new Pen(randomColor, size);
Graphics g = Graphics.FromImage(pictureBox1.Image);
g.DrawLine(selPen, 3, 3, 133, 133);
}
}

Try adding a
pictureBox1.Invalidate();
call.

This is not the right way to draw to a picture box:
private void pictureBox1_MouseDown(object sender,
MouseEventArgs m,
EventArgs e,
PaintEventArgs q)
{
if (m.Button == System.Windows.Forms.MouseButtons.Left)
{
Point currpoint = System.Windows.Forms.Cursor.Position;
Point origin = new Point(0, 0);
decimal sizee = nud.Value;
int size = Convert.ToInt32(sizee);
Random randonGen = new Random();
Color randomColor = Color.FromArgb(randonGen.Next(255),
randonGen.Next(255),
randonGen.Next(255));
Pen selPen = new Pen(randomColor, size);
using(Graphics g = pictureBox1.CreateGraphics()) // Use the CreateGraphics method to create a graphic and draw on the picture box. Use using in order to free the graphics resources.
{
g.DrawLine(selPen, 3, 3, 133, 133);
}
}
}
Btw, this method will create a temporary image which is reseted when the control is invalidated. For a more persistent drawing, you need to listen to the Paint event of the picture box and draw your graphics there.

You must draw it from image first. then attach it to pictureBox1
Bitmap canvas = new Bitmap(pictureBox1.Width, pictureBox1.Height);
Graphics g = Graphics.FromImage(canvas);
Point currpoint = System.Windows.Forms.Cursor.Position;
Point origin = new Point(0, 0);
decimal sizee = nud.Value;
int size = Convert.ToInt32(sizee);
Random randonGen = new Random();
Color randomColor = Color.FromArgb(randonGen.Next(255),
randonGen.Next(255),
randonGen.Next(255));
Pen selPen = new Pen(randomColor, size);
g.DrawLine(selPen, 3, 3, 133, 133);
pictureBox1.image = canvas;

This is an old question and if anyone else has a similar problem. See below. First let's examine the Ops code.
(1) See code: The first recommended change is to keep the Pen's format simple until we have a better understanding about how the Pen actually works when drawing to graphics. Look at the Op's line where we create graphics from image which is a perfectly good example of how to directly draw ("which means to write") to the supplied bitmap by use of the bitmap's graphics context. Next, the Op provides an excellent example of the Graphics DrawLine method which can draw the defined line to the supplied bitmap.
(2) Due to missing details we have to make the following assumptions about the Op's supplied bitmap and about their method for drawing a line to the bitmap. Assuming there already exists an image inside this pictureBox1; if an image is not set the graphics we get from image will be from a null image or that each pixel will be black just as a footnote:
(a) Is the Pen's color unique to the existing bitmap and is the alpha component of the color high enough to actually see the resultant color when it's drawn (when in doubt use a unique solid color or at least set the alpha channel to 255)?
(b) This line the Op wants to draw is starting Left 3, Top 3 to Left 133 and that is 3-pixels to the right of bitmap's left side where this line has a height of 133 and as such the Pen's line size was changed to a width = 3 for demonstration purposes.
(c) The final consideration, is the pictureBox1.Size sufficient for us to see this drawn line? The line's geometry forms a rectangle similar to this RectangleF(3, 3, 3, 133) structure, so if the pictureBox1 Bounds rectangle intersects with the derived line's rectangle then the area of that intersection is where the line could be drawn and considered visible.
Before we can draw to the pictureBox1 image from graphics we must first convert the pictureBox1 image data back to a usable image type like a bitmap for example. The reason is the picture box stores only pixel data in array format and is not directly usable by GDI/GDI+ without conversion to an image type ie. bitamp, jpeg, png etc..
One can avoid this messy conversion if you handle you own painting by the way of a custom user control and by properly handling the PaintEventArgs OnPaint implementation and/or by using related graphics screen buffer context scenarios.
For those who just want the answer about what's missing:
private void button1_Click(Object sender, EventArgs e)
{
Pen selPen = new Pen(Color.Red, 2); // The Op uses random color which is not good idea for testing so we'll choose a solid color not on the existing bitmap and we'll confine our Pen's line size to 2 until we know what we're doing.
// Unfortionately the picture box "image" once loaded is not directly usable afterwords.
// We need tp recreate the pictureBox1 image to a usable form, being the "newBmp", and for efficiency the bitmap type is chosen
Bitmap newBmp = new Bitmap(pictureBox1.Width, pictureBox1.Height, PixelFormat.Format32bppArgb); // Tip: Using System.Drawing.Imaging for pixel format which uses same pixel format as screen for speed
// We create the graphics from our new and empty bitmap container
Graphics g = Graphics.FromImage(newBmp);
// Next we draw the pictureBox1 data array to our equivelent sized bitmap container
g.DrawImage(pictureBox1.Image, 0, 0);
g.DrawLine(selPen, 3, 3, 3, 133); // Format: (pen, x1, y1, x2, y2)
pictureBox1.Image = newBmp;
// Don't forget to dispose of no longer needed resources
g.Dispose();
selPen.Dispose();
newBmp.Dispose(); // or save newBmp to file before dispose ie. newBmp.Save("yourfilepath", ImageFormat.Jpeg) or in whatever image type you disire;
}
The Op's code so far only draws a line to the bitmap's surface next if we are to "see" this change we must either save bitmap to file to be viewed later in an image viewer or we must draw the updated bitmap to our display monitor, the screen.
There are several methods with which to draw to your monitor's screen. The most common graphics contexts one could use are Control.CreateGraghics, graphics to screen method from (PaintEventArgs) and/or by using a graphics screen buffer sometimes called and used as a manual double buffered graphics context in which all is implemented by the way of DrawImage method from graphics.
The simplest solution, in this case based upon the Op's own code, is to display this newly updated bitmap using the pictureBox1 control. We'll simply update the control's image with the newly updated bitmap of course once first converted to a usage graphics image as seen in the above code descriptions.
Happy coding!

How to Zoom a Drawn Image in PictureBox

Hey everyone, a new guy here in C#.Net.
What I need is to zoom an image drawn using gdi+ to pictureBox.
I searched but couldn't find a nice answer, all I found was for existing files.
Does anyone has an idea?
Thanks for the answers.
My best Regards...

Use Transforms and Matrix objects as described here.
The example of scaling is given as
private void Scale_Click(object sender,
System.EventArgs e)
{
// Create Graphics object
Graphics g = this.CreateGraphics();
g.Clear(this.BackColor);
// Draw a filled rectangle with
// width 20 and height 30
g.FillRectangle(Brushes.Blue,
20, 20, 20, 30);
// Create Matrix object
Matrix X = new Matrix();
// Apply 3X scaling
X.Scale(3, 4, MatrixOrder.Append);
// Apply transformation on the form
g.Transform = X;
// Draw a filled rectangle with
// width 20 and height 30
g.FillRectangle(Brushes.Blue,
20, 20, 20, 30);
// Dispose of object
g.Dispose();
}

How to draw position sign?

I writing my own textbox control in C# for Winforms.
One thing i can't figure out: how to draw the text position sign in various sizes?

It is called the 'caret'. The winapi functions are not wrapped by winforms, you'll have to pinvoke them. Start reading here. You'll find code in my answer here.

Try this.
I created a method which is meant to be called from the paint handler of whichever control you're drawing in. For simplicity I just used the form itself in mine. You probably have a panel or some other control.
The method accepts the graphics object, the scale of the cursor and the upper/left position of where to start drawing. The scale is just the height but all the math is performed relative to the height. You can tweak those numbers any way you want.
private void Form1_Paint(object sender, PaintEventArgs e)
{
DrawCaret(e.Graphics, 30, new Point(20, 20));
DrawCaret(e.Graphics, 50, new Point(100, 100));
}
private static void DrawCaret(Graphics g, int scale, Point loc)
{
g.SmoothingMode = SmoothingMode.HighQuality;
int height = scale;
int width = scale/10;
int rectBase = scale/5;
g.FillRectangle(Brushes.Black, loc.X, loc.Y, width, height);
var path = new GraphicsPath();
path.AddPolygon(new[]
{
new Point(loc.X+width, loc.Y),
new Point(loc.X+width+rectBase/2, loc.Y+rectBase/2),
new Point(loc.X+width, loc.Y+rectBase),
});
g.FillPath(Brushes.Black, path);
}
This sample produces the following output: