I have a canvas that contains an Image in which I dislay an existing BMP. I draw rectangles on the canvas and add these to the Children colllection. When I click save, I want to update the underlying BMP file.
The following code works, but the rectangle that gets drawn to the BMP is way smaller than what I drew. I guess there's some difference in the co-ordinates? Maybe I shouldn't be using System.Drawing?
using (Graphics g = Graphics.FromImage(image))
{
g.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
foreach (var child in canvas.Children)
{
if (child is System.Windows.Shapes.Rectangle)
{
var oldRect = child as System.Windows.Shapes.Rectangle;
// need to do something here to make the new rect bigger as the scale is clearly different
var rect = new Rectangle((int)Canvas.GetLeft(oldRect), (int)Canvas.GetTop(oldRect), (int)oldRect.Width, (int)oldRect.Height);
g.FillRectangle(Brushes.Black, rect);
}
}
... code to save bmp
All suggestions welcome!
Thanks
Try using the System.Windows.Media.Imaging.RenderTargetBitmap Class (an example here).
Wpf uses Device Independent Graphics so you have to compensate for the DPI :
RenderTargetBitmap bmp = new RenderTargetBitmap((int)Canvas1.Width, (int)Canvas1.Height, 96, 96, PixelFormats.Default);
bmp.Render(Canvas1);
From Third Link:
There are two system factors that determine the size of text and graphics on your screen: resolution and DPI. Resolution describes the number of pixels that appear on the screen. As the resolution gets higher, pixels get smaller, causing graphics and text to appear smaller. A graphic displayed on a monitor set to 1024 x 768 will appear much smaller when the resolution is changed to 1600 x 1200.
Related
as you can read from the title i want to be able to draw some images on the screen, move them in some direction and video capture the movement with a good fps rate.
I want to specify that i do not want to record the desktop nor some portion of it but the content of the actual window in which the images are moving(so the window can also be minimized). Also if possible i want to be able to set a custom size for my view where everything will happen.
Where i should start from?
I have already tried with WPF but as the UI is single threaded i am not able to take a screenshot of the view while something is moving on it.
What library you would suggest me?
Are there similar open-source projects i can learn from?
Any suggestion i welcomed!
Here's some code I recently wrote to do this, it cycles through a number of frames and renders a control (in this case, a Canvas) into PNGs:
private void Export(int frame)
{
// force the control to update after any changes you've just made
theCanvas.Dispatcher.Invoke(DispatcherPriority.Render, EmptyDelegate);
// render the control into a bitmap
RenderTargetBitmap bitmap = new RenderTargetBitmap(1920, 1080, 96, 96, PixelFormats.Pbgra32);
bitmap.Render(theCanvas);
// save the bitmap out as a PNG
using (var stream = File.Create($"Animation/Frame_{frame.ToString("D3")}.png"))
{
var encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmap));
encoder.Save(stream);
}
}
You can then use ffmpeg to pack those PNGs into the movie file format of your choice.
In WPF ,we can use VisualBrush do some thing like ppt's left side.
But I see the VisualBrush may lost the line in Rectangle when I zoom the VisualBrush to a small size.Like the image:
You can see VisualBrush lost the Bottom line.
But what I want is like the below image:
When I try use the BitmapImage that use RenderTargetBitmap to get a image and use linear interpolation algorithm to zoom will get a clearness image.
Can I change VisualBrush's algorithm I think it may use neighborhood-pixels algorithm.
Are there any printscreen algorithm that have a good performance like VisualBrush.
When I change my search key to ViewBox ,I can find the same question as this one :how to avoid a single pixel line disappear in wpf?
There is a class named TransformedBitmap which can scale your RenderTargetBitmap with default scaling algorithm.
Use the code below:
public static BitmapSource ToBitmapSource(this Visual visual, Size size)
{
var bounds = VisualTreeHelper.GetDescendantBounds(visual);
var width = (int) Math.Round(bounds.Width);
var height = (int) Math.Round(bounds.Height);
var bitmap = new RenderTargetBitmap(width, height, 96.0, 96.0, PixelFormats.Pbgra32);
bitmap.Render(visual);
return new TransformedBitmap(bitmap, new ScaleTransform(size.Width / width, size.Height / height));
}
I've tried this method in my demo and got the result below. You may noticed that the small rectangle in the left-top corner lost nothing.
I have the requirement to create 600 DPI "trifold" images, which have the dimensions of 25.5"x11" (three times the size of a Letter page). To do so, I’m using WPF Imaging through the DrawingVisual, DrawingContext, and RenderTargetBitmap classes.
When I generate the image in lower resolutions, 400 DPI or less for example, all of the text displays in the correct positions as expected. However, once I increase my image resolution to the 500 DPI level and beyond, certain text positioned in the far right of the image will simply disappear, while other relatively positioned text/shapes print perfectly. The craziest part about it is that as I try varying DPIs, different text will appear/disappear. In one test case, 600 DPI is missing one set of drawn FormattedTexts, 650 DPI is missing a different set of drawn FormattedTexts, and 700 DPI prints everything fine!
I’ve recreated the issue with the snippet of code below. Run as-is (600 DPI) and all you get is a very large white image. Change the Dpi constant to 400 or lower, and it prints the text just fine.
Note that I’ve tried turning many of the knobs within the DrawingVisual class (e.g. VisualBitmapScalingMode, VisualTextRenderingMode, VisualEdgeMode, etc.) to no avail. Most of my research on those settings found them as useful settings to correct “fuzzy” text, not disappearing text. I’ve also had no luck with any of the guideline/snap settings of the DrawingVisual or DrawingContext.
Note that I’ve recreated this issue on both Win7 and Win2008R2, and my application is running .NET 4.5.
Any ideas?
const double ImageWidthInches = 25.5;
const double ImageHeightInches = 11.0;
const double Dpi = 600.0;
const double DeviceIndependentUnits = 96.0;
const double TypographicUnits = 72.0;
var visual = new DrawingVisual();
var drawing = visual.RenderOpen();
drawing.DrawRectangle(
Brushes.White,
null,
new Rect(0,
0,
ImageWidthInches*DeviceIndependentUnits,
ImageHeightInches*DeviceIndependentUnits));
var formattedText = new FormattedText(
"Why doesn't this display?",
CultureInfo.CurrentUICulture,
FlowDirection.LeftToRight,
new Typeface(new FontFamily("Arial Narrow"),
FontStyles.Normal,
FontWeights.Normal,
FontStretches.Normal),
8.0*DeviceIndependentUnits/TypographicUnits,
Brushes.Black);
drawing.DrawText(formattedText,
new Point(23.39*DeviceIndependentUnits,
2.6635416666666671*DeviceIndependentUnits));
drawing.Close();
var renderTarget = new RenderTargetBitmap(
(int) (ImageWidthInches*Dpi),
(int) (ImageHeightInches*Dpi),
Dpi,
Dpi,
PixelFormats.Default);
renderTarget.Render(visual);
var tiffEncoder = new TiffBitmapEncoder {Compression = TiffCompressOption.Ccitt4};
tiffEncoder.Frames.Add(BitmapFrame.Create(renderTarget));
using (var fileStream = new FileStream(#"c:\recreateWpfTextIssue.tif", FileMode.Create, FileAccess.Write))
tiffEncoder.Save(fileStream);
The workaround to this bug is to round the font size to 2 decimal positions:
Math.Round(8.0*DeviceIndependentUnits/TypographicUnits, 2),
This and some extra information can be found in the matching MSDN post: http://social.msdn.microsoft.com/Forums/en-US/98717e53-89f7-4d5f-823b-7184781a7b85/wpf-formattedtext-randomly-disappears-in-high-resolution-images
I have a TreeView with small icons displayed in the data template. I'm trying to save the Treeview as a PNG using RenderTargetBitmap.
The image saves correctly on small data sets. However, if the data set becomes too large, some of the icons are excluded from the final image. The magic number seems to be 200 items. It doesn't seem to matter if the tree is deep or wide, after 200 items, the icons are not rendered.
Added Code
So here is my code that I'm using to create an image.
RenderTargetBitmap targetBitmap = new RenderTargetBitmap(
(int)_treeView.ActualWidth,
(int)_treeView.ActualHeight,
96, 96, PixelFormats.Default);
targetBitmap.Render(_treeView);
Added Screen Shot
Notice the missing icons way over on the right side of the tree.
Now if I collapse a few branches, thus hiding some of the other icons, then these icons are included. It's almost like RenderTargetBitmap.Render doesn't have the power to render all of the icons. Or it may have something to do with virtual panels.
Here is a closer look.
What I immediately noticed that you have HUGE image. Width 12000. I am surprised that you even got that close.
As MSDN states, the texture width/height are limited by DirectX texture limits.
The maximum rendered size of a XAML visual tree is restricted by the maximum dimensions of a Microsoft DirectX texture; for more info see Resource Limits (Direct3D). This limit can vary depending on the hardware whre the app runs. Very large content that exceeds this limit might be scaled to fit. If scaling limits are applied in this way, the rendered size after scaling can be queried using the PixelWidth and PixelHeight properties. For example, a 10000 by 10000 pixel XAML visual tree might be scaled to 4096 by 4096 pixels, an example of a particular limit as forced by the hardware where the app runs.
http://msdn.microsoft.com/library/windows/apps/dn298548
I suspect these things:
Virtualization cutting off some things - I've had the exact problem in past with DataGrid, and the problem was virtualization. Your case doesn't seem like one though.
Too big texture can cause undefined behaviour.
You can try disabling hardware acceleration. The thing causes quite few hardcore bugs. http://msdn.microsoft.com/en-us/library/system.windows.media.renderoptions.processrendermode.aspx
Other than that - it will be tricky, but I am pretty sure that it will work beautifully:
1) start with the root object, and traverse the root object childrens recursively, until you find an object that is less than 1000 x 1000. Take picture of it using RenderTargetBitmap(BMP) and merge it to IN-MEMORY-BMP. Do it for each children.
You should be able to calculate all this stuff.
For the records: there's a workaround.
Instead of rendering your Visual directly with RenderTargetBitmap, use an interim DrawingVisual. Paint your Visual into the DrawingVisual using a VisualBrush and then use RenderTargetBitmap with the DrawingVisual.
Like this:
public BitmapSource RenderVisualToBitmap(Visual visual)
{
var contentBounds = VisualTreeHelper.GetContentBounds(visual);
var drawingVisual = new DrawingVisual();
using (var drawingContext = drawingVisual.RenderOpen())
{
var visualBrush = new VisualBrush(visual);
drawingContext.DrawRectangle(visualBrush, null, contentBounds);
}
var renderTargetBitmap = new RenderTargetBitmap((int)contentBounds.Width, (int)contentBounds.Height, 96, 96, PixelFormats.Default);
renderTargetBitmap.Render(drawingVisual);
return renderTargetBitmap;
}
Note however that as your VisualBrush gets bigger the resulting image gets more and more fuzzy (when rendering with high DPI). To work around this problem use a series of smaller VisualBrush "tiles" as described here:
https://srndolha.wordpress.com/2012/10/16/exported-drawingvisual-quality-when-using-visualbrush/
I have a print preview that displays a captured panel on a form 'Panel1.DrawToBitmap(memoryImage, bounds);'
I also save the image to my hard drive - 'memoryImage.Save("diary.png")'
The image in the print preview at any zoom level is blurry, the saved image is perfect (viewed in windows photo viewer & PS).
Id like the print preview to be as good as the saved image, any ideas?
here's the code:-
private void CaptureScreen()
{
int x = splitContainerDiary.Location.X;
int y = splitContainerDiary.Location.Y;
int SCwidth = splitContainerDiary.Panel1.Width;
int SCheight = splitContainerDiary.Panel1.Height;
Rectangle bounds = new Rectangle(x, y, SCwidth, SCheight);
memoryImage = new Bitmap(SCwidth, SCheight, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
splitContainerDiary.Panel1.DrawToBitmap(memoryImage, bounds);
memoryImage.Save("diary.png");
}
private void printDocumentDiary_PrintPage(object sender, PrintPageEventArgs e)
{
CaptureScreen();
Font HeaderFont = new Font("Consolas", 16, FontStyle.Bold);
e.Graphics.DrawString(selectedYear.ToString() + " - " + name, HeaderFont, Brushes.Black, 15, 15);
e.Graphics.DrawImage(Image.FromFile("diary.png"), 5, 5);
// e.Graphics.DrawImage(memoryImage, 0, 40);
PrintDoodle(e);
}
I have tried to draw the image from memory (e.Graphics.DrawImage(memoryImage, 0, 40) and also from the saved image 'e.Graphics.DrawImage(Image.FromFile("diary.png"), 5, 5);' They are both blurry in print preview.
I have tried different Pixel formats with no joy either.
I have tried saving the image as BMP, JPG, PNG with no joy either (when drawing image fromFile).
I have tried using BitBlt routine also with the same results.
Tino
This is an inevitable consequence of the dramatic difference between the device resolution of a printer vs a monitor. A printer typically can print with a resolution of 600 dots per inch. A monitor is typically set to 96 DPI. So when you print an image that's razor sharp on a monitor, each pixel of the image requires printing a blob of 6 x 6. Short from the blockiness this produces, anything that's drawn on screen with anti-aliasing will get those anti-aliasing pixels drawn 6 times larger as well. Completely ruining the effect. This is especially noticeable with any text that's drawn with ClearType anti-aliasing. The red and blue fringes become very noticeable on paper.
You can partly solve this by drawing the image one-to-one on the printer, ensuring that 1 pixel in the image becomes 1 pixel on paper. That ought to now look nice and sharp (minus the ClearType problem) but you'll be looking at a postage stamp. Growing your arms six times longer would have the same effect.
Well, this just doesn't work well. Use the PrintDocument class so you can draw stuff to the printer using its native resolution. Use the methods provided by e.Graphics in the PrintPage event handler. Avoid images unless they are photos, anything that doesn't have finely detailed line art will scale well.
I have encountered a similar "blurry font" problem, while trying to print out some custom text, which I've pre-arranged as Labels in the TableLayoutPanel.
My solution for the blurriness was as follows: I have created a panel and labels four times as big as the desired final size (by using font 44 instead of 11, and using width and height four times greater).
Then I've created a (large) bitmap, and downscaled it in the final step (DrawImage):
using (var bmp = new Bitmap(tableLayout.Width, tableLayout.Height))
{
tableLayout.DrawToBitmap(bmp, new Rectangle(0, 0, bmp.Width, bmp.Height));
printPageEventArgs.Graphics.DrawImage(
bmp,
printPageEventArgs.MarginBounds.X,
printPageEventArgs.MarginBounds.Y,
bmp.Width / 4,
bmp.Height / 4);
}
The resulting text looks much sharper both in the preview and in the actual printed page.
Of course, such an approach can only work if you can manipulate the Control's size, for example by creating it "off screen". But it will not work if you require the actual displayed control to be printed.