I am currently working on a C# application that aims to do some computation and output graphs in a pdf file.
I use the Zedgraph library to draw my graphs so something like graphPane.AddCurve(PointPairList). Now I tried to output these graphs to pdf file via MigraDoc package.
Currently, I have a script that map the Zedgraph to bitmap then paste it on the pdf file. So something like this:
private Bitmap getBitMap()
{
ZedGraphControl graph = new ZedGraphControl();
newGraph = graphPane.Clone();
SizeF s = new SizeF(3.5f, 4.5f);
newGraph.Scale(s);
newGraph.DrawToBitmap(bit, new Rectangle(0, 0, newGraph.Width, newGraph.Height));
return bit;
}
The problem is that this give me a slightly pixellated image on the pdf page. And I need this graph to be in a very high quality. So are there anything I can change the improve the quality or do i have to change my entire approach for such thing.
Thank you so much in advance.
By default a Bitmap you create has your current screen resolution which could be as low as 75dpi, more common 96dpi; more modern monitors have 120dpi or more, but a good print quality starts 150dpi. For really crips images you want 300dpi and to allow zooming you may want to have 600dpi or more..
So you need to create and fill a bitmap with a larger size and take control of its dpi resolution.
Assuming your size of 3.5f x 4.5f is inches, for 300dpi you need a Bitmap with 1050 x 1350 pixels.
So you should create such a Bitmap..:
Bitmap bmp = new Bitmap(1050, 1350);
..and set the resolution:
bmp.SetResolution(300, 300);
To fill it up your control must have the same size:
newGraph.ClientSize = bmp.Size;
Now DrawToBitmap should create an image that is crisp and fit to zoom in..
Note that it does not matter if the control is too large to fit on the screen; DrawToBitmap will still work.
Update In addidtion to a sufficient resolution it is of interest to draw quality lines etc.. A speciality of ZedGraph is that one can turn on Antialiasing, either for individual lines:
curve_x.Line.IsAntiAlias = true;
or other elements:
myPane.XAxis.Scale.FontSpec.IsAntiAlias = true;
or the whole Chart:
zedGraphControl1.IsAntiAlias = true;
All examples are taken from this post.
Related
I'm working on a project which generally is collecting data and drawing results in charts. (Using C#) I need to save my charts in a PDF file. My question is, how to save charts in a PDF file without loosing resolution? My point is how to draw vector graphics instead of raster graphics?
I tried iTextSharp to create PDF file but the result is not satisfying at all!
I'm new here, so I'm not able to upload pictures.
Here is the result after saving my file:
https://www.dropbox.com/s/ruwtc82hfosxk6y/Test.pdf?dl=0
Here is the PDF that I need to create:
https://www.dropbox.com/s/jvu5uu069imo9xc/nir%20well%20abfar.pdf?dl=0
There are two ways I know of to get high-quality images from your Chart into a PDF.
One is by using vector formats:
Use chart.SaveImage with one of the three emf formats.
Convert the resulting emf file to wmf
Insert the wmf file into your iTextSharp document.
1 and 3 are one-liners. But step 2 is not. In fact I haven't found a working c# solution at all. The best was a weird reference to an edit that has disappeared here ..
If you can use some other program to do the conversion you will get nice results like this demo pdf file.. I used Illustrator for the conversion.
Two: If you can't get step 2 to work, you can still get nice results, if you use raster images with a nice and high resolution. Here is how to do it:
First we hide the Chart, so we don't scare the user. Then we make it as large as we want the output to be. Then we DrawToBitmap and finally we reset the chart again..:
Size s = chart1.Size;
chart1.Hide();
// pick your size in pixels
// I simply multiply my screen size..:
chart1.Size = new System.Drawing.Size(s.Width * 5, s.Height * 5);
using (Bitmap bmp = new Bitmap(chart1.ClientSize.Width, chart1.ClientSize.Height))
{
// you should set the resolution,
// although I didn't find a way for iTextSharp to use it visually
bmp.SetResolution(600, 600);
using (Graphics G = Graphics.FromImage(bmp))
{
G.SmoothingMode = SmoothingMode.HighQuality;
G.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
chart1.DrawToBitmap(bmp, chart1.ClientRectangle);
bmp.Save(yourImageFile, ImageFormat.Png);
}
}
chart1.Size = s;
chart1.Show();
You could also use SaveImage and save a few lines, but you can't set the resolution of the png file there and it will be saved at the currnt screen resolution, which is 96dpi here..
Now you have a large image and will probably have to scale it down in iTextSharp:
iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(yourImageFile);
img .ScalePercent(15); // scale to fit your needs..
doc.Add(img );
Note that the legend and the labels get very small this way, so you may have to enlarge them before saving. I also found that, when scaling down, the image is rather bright until you zoom in..
Here are two screenshots, one from the chart, the other from the pdf documnet after zooming in a lot (300%)..:
I updated a chart from essentially being 72dpi, to 300dpi. This is because I am using itextsharp to add an image to my pdf and the quality was poor. So I increased the size of the image by 3X and the image does look better, but here is the problem.
DPI has increased, but detail has become very hard to see.
Original Chart Image
Refactored Chart Image
Code
This is how I resized my chart.
private static System.Drawing.Bitmap GetChartBitmap()
{
System.Drawing.Rectangle targetBounds = new System.Drawing.Rectangle(0, 0, chart_runs.Width, chart_runs.Height);
System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(targetBounds.Width, targetBounds.Height);
bitmap.SetResolution(1000, 1000);
chart_runs.DrawToBitmap(bitmap, targetBounds);
bitmap.Save(#"C:\Temp\OriginalChartImage.bmp");
System.Drawing.Bitmap bitmap3 = new System.Drawing.Bitmap(1650, 990);
bitmap3.SetResolution(300, 300);
chart_runs.DrawToBitmap(bitmap3, new System.Drawing.Rectangle(0, 0, 1650, 990));
bitmap3.Save(#"C:\Temp\RefactoredChartImage.png");
//This stuff below is for my code elsewhere. Using bitmap3 to be added to pdf.
//chart_runs.DrawToBitmap(bitmap, targetBounds);
string path = System.IO.Path.GetTempPath();
bitmap1.Save(path + #"\Image.png");
return bitmap1;
}
I have looked at the Microsoft msdn examples and haven't found anything that addresses my problem. Namely, how can I either increase the size of my labels so people can read them again. OR, is there a way for me to increase the DPI and keep the same label x and label y scale that was used in the first picture? That is, have a larger image and 300DPI, but scale 0 to 300 by 20's and not 5's like my refactored picture?
Attempts to fix
Scaling the axis? See here. I don't think this is working right. Not much success here.
Been trying to find a way in Chart class to see if there is a way to specify strict scales. (20 on y scale vs 15 seconds on x scale).
Most online resources are pleased just to increase the scale of the picture and walk away. And things like this here.
I would greatly appreciate any help and assistance.
Couple different questions, with a couple different answers. The easiest would be to change the font size of your axis labels to be bigger. This can be done via
chart1.ChartAreas[0].AxisX.LabelStyle.Font = new Font...;
Without doing that, your labels won't be readable no matter what else you do, and that's just because you changed the DPI (that's exactly what changing the DPI does).
If you want the labels to be displayed every 20 units on the y axis and every 15 on the x, you can use the Interval and IntervalType properties of the axis. The IntervalType is used when you have DateTime objects being displayed:
chart1.ChartAreas[0].AxisX.Interval = 15;
chart1.ChartAreas[0].AxisX.IntervalType = DateTimeIntervalType.Seconds;
chart1.ChartAreas[0].AxisY.Interval = 20;
Your first link about scaling the axis is essentially zooming in or out, which is why you haven't had success.
I'm trying to put high quality images into PDF (one per page). But if I set page size to a4, I have to resize my pictures, becouse they're too large. Then they loose their quality. Is there any way to put big image to a4 page without loosing quality?
I'm using iTextSharp library, firstly I'm creating the document
document = new Document(PageSize.A4, 0, 0, 0, 0);
FileStream output = new FileStream(pdfPath + "document.pdf", FileMode.Create);
PdfWriter writer = PdfWriter.GetInstance(document, output);
document.Open();
then I'm adding each picture
document.Add(iTextSharp.text.Image.GetInstance(toSaveImage, System.Drawing.Imaging.ImageFormat.Tiff));
and closing the document
document.Close();
First let me clear a couple of misunderstandings:
a PDF document doesn't have a resolution. The comment by spender was wrong. There is no such thing as DPI in PDF. The resolution only comes into play when a PDF is rendered (to the screen, to paper,...) and that's why there may be a DPI in a PDF viewer (but that's something completely different).
when you scale an Image object in iTextSharp, you don't lose any information: the number of pixels remains the same. Whereas PDF doesn't have a resolution, the images inside a PDF do. When you the image scale down (that is: you put the same number of pixels on a smaller canvas), the resolution increases; when you scale up, the resolution decreases.
Now for your question: you're not obliged to create A4 pages:
Image img =
iTextSharp.text.Image.GetInstance(toSaveImage,
System.Drawing.Imaging.ImageFormat.Tiff);
Rectangle pagesize = new Rectangle(img.ScaledWidth, img.ScaledHeight);
Document document = new Document(pagesize);
img.SetAbsolutePosition(0, 0);
document.Add(img);
I created the Document based on the scaled dimensions of the Image. Don't let the method names mislead you: ScaledWidth and ScaledHeight are the safest methods to use when getting the dimensions of an Image. Not only do they include any scaling operations, you may have done on the image, the also take into account the space needed for the image after rotating it.
I've set the absolute position to the lower-left corner. That's safer than setting the page margins to 0.
EDIT: If you don't want to change the page size, then you have to use the ScaleToFit() method:
Image img =
iTextSharp.text.Image.GetInstance(toSaveImage,
System.Drawing.Imaging.ImageFormat.Tiff);
img.ScaleToFit(PageSize.A4);
Note that the method to scale to fit to a Rectangle object was introduced in one of the latest iTextSharp versions. An alternative would be to use the ScaleToFit() method that requires the width and the height of the rectangle.
My application is used to design airports for a flight simulator. Users can add one or more images as background. The image(s) can be sized accurately and then used as a template to lay down features such as runways, aprons and so on.
I use a third party graphics library (Piccolo) which has an image class (as far as I can see it is a simple wrapper for System.Drawing.Image).
So far I have done little except allow the user to add an image, size it and so on. It will be no surprise that users sometimes complain of poor performance. We tell them not to load large images (up to 100k seem OK) but don't stop them and 100Mb bitmaps have been used with horrible results.
I need to fix this in a couple of ways. First by converting any image they use to an efficient format (size vs definition) and second by ensuring that the loaded image is suitably sized for the dimensions - at the moment I don't do anything specific to deal with the resizing of say a 2000 x 2000 image to fit a 500 x 500 area of the display.
The default 1:1 display of the application represents 1m per pixel. Once the user has resized the image to fit accurately would I be right in thinking that the best resoultion for the image would be to resample it to that size? I am aware that if the user zooms in way past 1:1 which they will probably do then the clarity of the image will fall.
My ignorance of handling images is complete. I have looked at some image manipulation libraries (ImageMagick and the free version of dotIamge) first for converting the input image to a standard one and second for resizing -resampling. The truth is that they do far more than I need.
Any pointer much appreciated.
Yes, resampling so that the bitmap doesn't constantly have to be rescaled for every paint should make a big difference. The default Graphics.InterpolationMode makes pretty images but is not cheap.
Another biggie is the pixel format of the bitmap. Format32bppPArgb is 10 times faster than any of the others on most video adapters.
private static Bitmap Resample(Image img, Size size) {
var bmp = new Bitmap(size.Width, size.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
using (var gr = Graphics.FromImage(bmp)) {
gr.DrawImage(img, new Rectangle(Point.Empty, size));
}
return bmp;
}
This is the high level problem I'm trying to solve...
I have a 3rd party plotting/graphing (IoComp Plot), and I want to embed a high quality (at least 600 dpi) bitmap of the Plot control in reports created by another 3rd party report package (Combit List & Label).
This is the approach that seems most promising so far...
---Edit---:
After trying many other approachs, the only one that I think I can make work is to create a hidden instance of the Plot control, with everything scaled up to printer size (approx 5 times screen size). That includes width and height, font sizes, line widths - every visible component of the control. Yuck!
------
I can get a Graphics object of the proper resolution from the plot control's PrintPage event, but converting it to a Bitmap so the report package will be happy is proving to be the major stumbling block. Several hours of searching has led to other people who asked the same question, but no viable answers.
The only promising lead I've found suggested using one of the Bitmap constructors, which takes a Graphics instance as a parameter.
However, it's not working for me. It creates Bitmap, but with no content from the Plot control - it is a pure black image.
Here's my code (edited to show drawing of red line to Graphics object):
void PrintDocument_PrintPage(object sender, PrintPageEventArgs e)
{
// Draw a red line on the Graphics object. When printed, this
// line is shown as part of the normal Plot graphics.
Pen myPen;
myPen = new Pen(Color.Red);
e.Graphics.DrawLine(myPen, 0, 0, 200, 200);
myPen.Dispose();
// Create a bitmap from the Graphics object
Bitmap bm = new Bitmap(1000, 1000, e.Graphics);
// Save to disk
// DOES NOT WORK - CREATES FILE THAT IS PURE BLACK (VIEWED
// WITH "PAINT" PROGRAM)
bm.Save(#"C:\Bicw_Dev\Bic.Net\FrontEnd\GraphicsToBmp.bmp", ImageFormat.Bmp);
bm.Dispose();
}
Can anyone suggest why this doesn't work? Is this even a valid approach?
Also, please note:
As far as I can determine (and I've spent quite a bit of time looking) there is no way to get a high resolution, print quality Bitmap from the Plot control directly!
I stress this because several others who asked the question got code samples in response that solved the opposite problem - converting a Bitmap to a Graphics.
I need to convert a Graphics object to a Bitmap object.
And if anyone can suggest an alternate approach that allows me to get a print quality image of my plots into my reports, please feel free. (For example, I can get a low quality (72 bpi) Bitmap from the Plot control, and have considered trying to stretch it - but I've never seen that approach work well in other applications).
Thanks,
-Tom Bushell
Edit in response to comment:
As an experiment, I added the following:
Pen myPen;
myPen = new Pen(Color.Red);
e.Graphics.DrawLine(myPen, 0, 0, 200, 200);
myPen.Dispose();
This caused a red line to be drawn over the plot graphics when I printed my plot. But it had no effect on the Bitmap - it's still pure black.
However, it's not working for me. It
creates Bitmap, but with no content
from the Plot control - it is a pure
black image.
Well you never do paint to the graphics, what do you expect?
You are suppose to do the actual drawing for the output in that event.
The constructor you're using does not copy any graphics, only sets the resolution equal to the graphics resolution. See msdn. As Leppie points out, you have to actually draw something to the bitmap. I suggest getting another graphics object for the item you just created.
Graphics g = Graphics.FromImage(bmp);
//Make the background white
g.FillRectangle(Brushes.White, 0, 0, 1000, 1000);
It is not easy to control the DPI in the Print(Preview) system.
But maybe you are going about it the wrong way. What you want is to create a (large) bitmap and then 'trick' the control in to using that bitmap as if it was the screen. See this list of links.
No need for PrintDocument.