Develop Reference

split image to multiple image from the bottom up

I have a picture I want to print, but it's too big for one page
so i have decided to split it into multiple images
i have tried a method, but now im using this (Talha Irfan answer)
i also tried the other solutions there but those didnt worked as well
(ex. bm.Clone(rec, bm.PixelFormat);)
and here's my code(this is on non-form class)
Bitmap bm = new Bitmap(frmPrint.Width, frmPrint.Height);
Rectangle rec = new Rectangle(0, 200, 576, 300);
Bitmap bitmap = cropImg(bm, rec);
frmPrint.DrawToBitmap(bitmap, rec);
frmPrint._img = bitmap;
frmPrint.setImage();
and setImage function(on some form)
public void setImage()
{
pictureBox3.BackgroundImage = _img;
this.ShowDialog();
}
and cropImg is the same as cropAtRect
the below shows the original image (on the left)
the wanted result in the blue rectangle
and the actual result on the right
PS
my actual image size is (height = 698, wifht = 576)
Edit - as suggested below
on non-form class
Rectangle cropRect = new Rectangle(0, 0, 576, 698);
Bitmap target = new Bitmap(cropRect.Width, cropRect.Height, bm.PixelFormat);
frmPrint.setImage(bm, target, cropRect);
target.Dispose();
at form class
public void setImage(Bitmap src, Bitmap target, Rectangle cropRect)
{
pictureBox3.Visible = false;
using (Graphics g = Graphics.FromImage(target))
{
g.DrawImage(src, new Rectangle(pictureBox3.Location.X, pictureBox3.Location.Y, target.Width, target.Height),
cropRect,
GraphicsUnit.Pixel);
}
this.ShowDialog();
}

Control.DrawToBitmap will always try to draw the whole control or form and will always start at the top. The parameter:
targetBounds
Type: System.Drawing.Rectangle
The bounds within which the control is rendered.
as the name implies, sets the target, not the source rectangle. Hence the white space above your result.
Move the line before cropping with a rectangle that holds the full area, maybe like this:
DrawToBitmap(bm, ClientRectangle);
and then crop the lower part as before..
Note that the cropping trick from your link will not work for DrawToBitmap; using a rectangle with a negative offset will cause a parameter exception.
Btw: to safely dispose of a Bitmap in a PictureBox use this:
Bitmap dummy = (Bitmap )somePictureBox.Image;
somePictureBox.Image = null;
if (dummy != null) dummy.Dispose;
And, indeed, the answer by ChrisJJ in the link leaks the Graphics object.
Update:
Since you seem to have lost control over the various changes and suggestions, here is the minimal code change from the original post:
Bitmap bm = new Bitmap(frmPrint.ClientWidth, frmPrint.ClientHeight);
DrawToBitmap(bm, frmPrint.ClientRectangle);
Rectangle rec = new Rectangle(0, 200, 576, 300);
Bitmap bitmap = cropImg(bm, rec);
frmPrint._img = bitmap;
frmPrint.setImage();
With:
public void setImage()
{
Bitmap dummy = pictureBox3.BackgroundImage;
pictureBox3.BackgroundImage = null;
if (dummy != bnull) dummy.Dispose();
pictureBox3.BackgroundImage = _img;
this.ShowDialog();
}
In the cropImg function add a g.Dispose before returning.

Unable to get correct Size of DrawnText using TextRenderer

Im drawing Text using the following code onto a Bitmap
GraphicsPath pth = new GraphicsPath();
var style = (int)myfont.Style;
pth.AddString(tcaption.Text, myfont.FontFamily, style, myfont.Size, point, StringFormat.GenericTypographic);
p = new Pen(new SolidBrush(bc), 2f);
mygraphics.DrawPath(p, pth);
I'm using the TextRenderer to measure the size of the string..
int Width = TextRenderer.MeasureText(tcaption.Text, myfont).Width;
But this does not produce the correct size of the drawn string; there is around 20-30% difference from the actual size of the drawn string?
What im i doing wrong? Please advice.
UPDATE:
I want to draw a Text and an Image onto a Bitmap,so inorder to accommodate both i'm creating an Bitmap like this
intWidth = TextRenderer.MeasureText(tcaption.Text, cfont).Width + image.Width;
intHeight = TextRenderer.MeasureText(tcaption.Text, cfont).Height +image.Height;
tempimage= new Bitmap(intWidth, intHeight);
Then i create Graphics object from the Bitmap like this
using (Graphics newg = Graphics.FromImage(tempimage))
#Hans Passant
I have also tried the Graphics.MeasureString as an alternative to TextRenderer
Now i set the position of the text and image-I need to draw the image at the top left corner .. so
imageposy = 0;
imageposx = 10;
textposy = image.Height;
textposx = 0;
Then i draw the text like this
po=new Point(textposx, textposy);
newg.SmoothingMode = SmoothingMode.AntiAlias;
GraphicsPath pth = new GraphicsPath();
var style = (int)myfont.Style;
pth.AddString(tcaption.Text, myfont.FontFamily, style, myfont.Size, po,
StringFormat.GenericTypographic);
newg.FillPath(new SolidBrush(fc), pth);
Now i draw the image like this
Rectangle nrect = new Rectangle(imageposx, imageposy, image.Width,
image.Height);
objGraphics = Graphics.FromImage(tempimage);
objGraphics.DrawImage(image, nrect);
As you have seen i need to add the offset 10 to imageposition x coordinate to correct the measurement issue.
Hope my update throws more light into the question... what im i doing wrong?
Please advice..

instead of using TextRenderer use GraphicsPath:
var path = new GraphicsPath();
path.AddString(text, font.FontFamily, (int)font.Style, size, new Point(0, 0), StringFormat.GenericTypographic);
var area = Rectangle.Round(path.GetBounds());
Here is sample code that generates image with size of text:
private Image DrawText(String text, Font font, int size, Color textColor, Color backColor)
{
var path = new GraphicsPath();
path.AddString(text, font.FontFamily, (int)font.Style, size, new Point(0, 0), StringFormat.GenericTypographic);
var area = Rectangle.Round(path.GetBounds());
Rectangle br = Rectangle.Round(path.GetBounds());
var img = new Bitmap(br.Width, br.Height);
var drawing = Graphics.FromImage(img);
drawing.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;
drawing.SmoothingMode = SmoothingMode.HighSpeed;
drawing.Clear(backColor);
drawing.TranslateTransform((img.Width - br.Width) / 2 - br.X, (img.Height - br.Height) / 2 - br.Y);
drawing.FillPath(Brushes.Black, path);
Brush textBrush = new SolidBrush(textColor);
drawing.Save();
textBrush.Dispose();
drawing.Dispose();
return img;
}
Here are sample results:

Is it possible to rotate a drawing half-way its definition?

I'm doing some draws that are repetitive, and each of them gives lot of work.
What i need to do is rotate the drawing half-way its definition, something like this:
using (Graphics g = Graphics.FromImage(bmp))
{
//define area do pictureBox e preenche a branco
Brush brush = new SolidBrush(Color.White);
Rectangle area = new Rectangle(0, 0, 520, 520);
g.FillRectangle(brush, area);
//rotate
g.RotateTransform(some angle, some reference point)
//draw some more lines on the top of the rotated previous ones.
}
I tried using g.RotateTransform(90) as there is that function in Winforms, but it didn't change anything. Why??
Any tip?
Edit: if it helps, i only need to rotate fixed angles, 180º

RotateTransform certainly does change the subsequent drawing.
Note that you usually need a TranslateTransform before to set the rotation point. But it 'it didn't change anything' is certainly wrong. Try again! And yes you can rotate (or scale or move) at any point and move/turn it back or completely reset the Graphics object.
And yes, learning about Matrix and MultiplyTransform is also very helpful..
But: You need to understand the Graphics object does not contain any graphic, a common misconception! It is the tool which does the drawing on a Bitmap, most often the surface of a Control. So the rotation will happen but only for the things you draw after:
private void panel1_Paint(object sender, PaintEventArgs e)
{
Rectangle rect = new Rectangle(25, 25, 25, 25);
e.Graphics.TranslateTransform(25, 25);
e.Graphics.FillRectangle(Brushes.Red, rect);
for (int i = 0; i < 15; i++)
{
rect.Inflate(2, 2);
e.Graphics.TranslateTransform(5, 2);
e.Graphics.RotateTransform(2.5f);
e.Graphics.DrawRectangle(Pens.Blue, rect);
}
}

Try this:
use these references:
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
I made windows application and put on form1 picturebox then this is the code in form_load:
//Load an image in from a file
Bitmap pImage = new Bitmap(Environment.CurrentDirectory + #"\Image.bmp", true);
//Set our picture box to that image
pictureBox1.Image = (Bitmap)pImage.Clone();
//Store our old image so we can delete it
Image oldImage = pictureBox1.Image;
//Pass in our original image and return a new image rotated 35 degrees right
pictureBox1.Image = RotateImage(pImage, 270);
if (oldImage != null)
{
oldImage.Dispose();
}
Then make static function with parameters of image and rotation angle return the rotated image and call it from form_load as mentioned before :
if (image == null)
{
throw new ArgumentNullException("image");
}
else
{
//create a new empty bitmap to hold rotated image
Bitmap rotatedBmp = new Bitmap(image.Width, image.Height);
rotatedBmp.SetResolution(image.HorizontalResolution, image.VerticalResolution);
//make a graphics object from the empty bitmap
Graphics g = Graphics.FromImage(rotatedBmp);
//move rotation point to center of image
g.TranslateTransform((float)image.Width / 2, (float)image.Height / 2);
//rotate
g.RotateTransform(angle);
//move image back
g.TranslateTransform(-(float)image.Width / 2, -(float)image.Height / 2);
//draw passed in image onto graphics object
g.DrawImage(image, new PointF(0, 0));
return rotatedBmp;
}

You can also use directly the code in form_load by using ready RotateFlipType (Enumeration type) but this with fixed angles like 90,270,.... but the previous method you can use any integer values to rotate the image :
private void Form1_Load(object sender, EventArgs e)
{
//Load an image in from a file
Bitmap pImage = new Bitmap(Environment.CurrentDirectory + #"\Image.bmp", true);
pImage.RotateFlip(RotateFlipType.Rotate90FlipXY);
pictureBox1.Image = pImage;
}

Use croppic to rotate images

I am using croppic to crop images. Is there any possibility to extend its functionality to rotate the image, before sending it to crop. Something like this
var angle = 0;
$('#button').on('click', function() {
angle += 90;
$("#image").rotate(angle);
});
Here is the demo
I can manage to to rotate the image, but the cropped image is not in rotated position. Any idea?
Update:
Now the image is getting rotated. I have managed to keep rotated image by the same handler that uses crop method. But the cropped image in rotated position occurs only when the rotated image is in 180 rotation. When its in the 90/270, the image, obviously don't fit in the bounding box (if you have seen croppic) and I get a MemoryOutOfBound exception.
Here is the code:
public static Bitmap RotateImage(Bitmap bmpSrc, float theta)
{
Matrix mRotate = new Matrix();
mRotate.Translate(bmpSrc.Width / -2, bmpSrc.Height / -2, MatrixOrder.Append);
mRotate.RotateAt(theta, new System.Drawing.Point(0, 0), MatrixOrder.Append);
using (GraphicsPath gp = new GraphicsPath())
{ // transform image points by rotation matrix
gp.AddPolygon(new System.Drawing.Point[] { new System.Drawing.Point(0, 0), new System.Drawing.Point(bmpSrc.Width, 0), new System.Drawing.Point(0, bmpSrc.Height) });
gp.Transform(mRotate);
System.Drawing.PointF[] pts = gp.PathPoints;
// create destination bitmap sized to contain rotated source image
Rectangle bbox = boundingBox(bmpSrc, mRotate);
Bitmap bmpDest = new Bitmap(bbox.Width, bbox.Height);
using (Graphics gDest = Graphics.FromImage(bmpDest))
{ // draw source into dest
Matrix mDest = new Matrix();
mDest.Translate(bmpDest.Width / 2, bmpDest.Height / 2, MatrixOrder.Append);
gDest.Transform = mDest;
gDest.DrawImage(bmpSrc, pts);
return bmpDest;
}
}
}
private static Rectangle boundingBox(Image img, Matrix matrix)
{
GraphicsUnit gu = new GraphicsUnit();
Rectangle rImg = Rectangle.Round(img.GetBounds(ref gu));
// Transform the four points of the image, to get the resized bounding box.
System.Drawing.Point topLeft = new System.Drawing.Point(rImg.Left, rImg.Top);
System.Drawing.Point topRight = new System.Drawing.Point(rImg.Right, rImg.Top);
System.Drawing.Point bottomRight = new System.Drawing.Point(rImg.Right, rImg.Bottom);
System.Drawing.Point bottomLeft = new System.Drawing.Point(rImg.Left, rImg.Bottom);
System.Drawing.Point[] points = new System.Drawing.Point[] { topLeft, topRight, bottomRight, bottomLeft };
GraphicsPath gp = new GraphicsPath(points,new byte[] { (byte)PathPointType.Start,
(byte)PathPointType.Line, (byte)PathPointType.Line,
(byte)PathPointType.Line });
gp.Transform(matrix);
return Rectangle.Round(gp.GetBounds());
}
I think main issue is in the bounding box.
using (Bitmap rotate = new Bitmap(RotateImage(bmp, rotateAngle)))
{
using (Bitmap cloneRotate = (Bitmap)rotate.Clone()) //getting error here
{
//some stuffs
cloneRotate.save(mycroppedimageurl);
}
}

C# redaction drawing on Image

Whats going on is i need to draw a black rectangle over the image. I have to load a tif and then show a blackbox over it. I was helped with some code but i continously got the error: A Graphics object cannot be created from an image that has an indexed pixel format.
So i had to read it in to bit format, but when i display the box it resizes the box wierd. And completly displays the the picture box in all black nothing of the original image. if someone could help me where i'm going wrong that would be awesome.
Bitmap original = (Bitmap)System.Drawing.Image.FromFile(coveted, true);
Bitmap newImage = new Bitmap(original.Width, original.Height);
pictureBox1.Image = newImage;
using (Graphics g = Graphics.FromImage(pictureBox1.Image))
{
using (SolidBrush brush = new SolidBrush(Color.Black))
{
g.FillRectangle(brush, new Rectangle(x1value, y1value, x3value, y3value));
}
}
I'm not sure how I can make this clearer. Whats happening is I have a tif in a unsupported format. So I have to change it to a Bitmap so I can actually draw a rectangle on it. Then I need to display this redacted image (the original with the redaction) in a picturebox. Whats going on with the code above, is once it's completed, all it displays is a blackbox with no original image.
I believe i ran something about using a Bitmap from stream and then closing the stream. Anybody familiar with this?
Thanks to all the help from STO members!! heres the correct code for redacting images if you encounter the error "A Graphics object cannot be created from an image that has an indexed pixel format.".
if you're given the redacted starting points (obviously you have to make the Regex work to your situation):
//Regex for pulling points from a file
string x1 = x1 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)").Groups[2].Value;
string y1 = y1 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)\r\n(\d+)").Groups[3].Value;
string x2 = x2 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)").Groups[4].Value;
string y2 = y2 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)").Groups[5].Value;
string x3 = x3 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)").Groups[6].Value;
string y3 = y3 = Regex.Match(l, #"\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)\r\n(\d+)").Groups[7].Value;
{
//convert string to int for redacted points
int x1value = Convert.ToInt32(x1);
int y1value = Convert.ToInt32(y1);
int x3value = Convert.ToInt32(x3);
int y3value = Convert.ToInt32(y3);
{
//BEGIN Workaround for indexed pixels
Bitmap original = (Bitmap)System.Drawing.Image.FromFile(YOURFILE, true);
Bitmap newImage = new Bitmap(original);
pictureBox1.Image = newImage; //END Workaround for indexed pixels
using (Graphics g = Graphics.FromImage(pictureBox1.Image)) //start redaction
{
using (SolidBrush brush = new SolidBrush(Color.Black))
{
g.DrawImageUnscaled(newImage, 0,0);
g.FillRectangle(brush, new Rectangle(x1value, y1value, x3value, y3value));
}
} //End Redaction
pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage; //Resized to fit into a static picturebox
}
}

Instead of
Bitmap newImage = new Bitmap(original.Width, original.Height);
you want
Bitmap newImage = new Bitmap(original);
This will make your newImage start with the contents of original.
The difference will be that you will end up with newImage.PixelFormat == PixelFormat.Format32bppArgb, while I'm assuming original.PixelFormat == PixelFormat.Format1bppIndexed.
With PixelFormat.Format32bppArgb, you can create a Graphics object; you cannot with PixelFormat.Format1bppIndexed.

This should work for you:
original = (Bitmap)System.Drawing.Image.FromFile(coveted, true);
using (Graphics g = Graphics.FromImage(original))
{
using (SolidBrush brush = new SolidBrush(Color.Black))
{
g.FillRectangle(brush, new Rectangle(x1value, y1value, x3value, y3value));
}
}
pictureBox1.Image = original;

You aren't drawing the original image on the newImage.
To do so :
g.DrawImageUnscaled(original, 0, 0);
Also, I would do it as follows, I think it works better drawing in RAM, and then showing it to screen. Perhaps I'm wrong though.
using (Graphics g = Graphics.FromImage(newImage))
{
g.DrawImageUnscaled(original, 0, 0);
using (SolidBrush brush = new SolidBrush(Color.Black))
{
g.FillRectangle(brush, new Rectangle(x1value, y1value, x3value, y3value));
}
}
pictureBox1.Image = newImage;
I haven't tested the code above.. good luck though.