I'm developing a C# forms application, and I need to render HTML during the paint event of a PictureBox control.
Showing just the relevant part, this is the way I would like to do this.
private void CustomPictureBoxPaint(object sender, PaintEventArgs e) {
Graphics g = e.Graphics;
//render html as on g
}
I found a NuGet library which is able to do it this way. HtmlRenderer.Core has a HtmlRenderer class.
private void CustomPictureBoxPaint(object sender, PaintEventArgs e) {
Graphics g = e.Graphics;
Image image = HtmlRender.RenderToImage(htmlText,new Size(150,150) //htmlText has the HTML as string
g.DrawImage(image,point);
}
But there is one big restriction for it: the background can't be transparent. It is something I need, so my question is the following:
Is there a library which is capable of rendering html with transparent background on a PictureBox, or any other way to achieve my goal?
Alternatively rendering markdown instead of html is also a good solution for me, if there is a way to do it.
Related
I'm working on a graphic application in C# windows form app. I have a form that I can draw on it.
so I created a Graphic object from the form.
void StartPoint()
{
Graphics graphic;
graphic = PaintWindow.CreateGraphics();
}
I want to know how can I export this graphic as a png or jpg file after drawing something.
before this, I searched for this question but I didn't find any useful.
some people resolve this with printing that part of the screen:
graphic.CopyFromScreen(...);
this way is not useful for me because some times I need to transparent my background image.
also, I tried Bitmap way :
private void ExportBTN_Click(object sender, EventArgs e)
{
Bitmap b = new Bitmap(PaintWindow.Width, PaintWindow.Height, graphic);
b.Save(...);
}
but when I save, the image file is completely black.
this is my application:
If you want to draw to an image you want to create your graphics from that image:
using(var myGraphics = Graphics.FromImage(myBitmap))
{
// Do drawing
}
You can then proceed to to use CopyFromScreen and other drawing methods to update the image and then save it.
C# Beginner here.
I'm making a 2D Tanks game, and everything's working out nicely so far.
Both of my tanks are Picture Boxes, and so is my Missile.
The image of the missile and tanks in the PictureBoxes have transparent BackColour properties. The problem is, the background of the missile & tanks are not transparent while on top of the other picturebox (pbBackground). It looks like this.
I'm aware that using different PB's is an inefficient way of going about it, but I've come pretty far and I don't really know any better. Anyways, as you can see, the Missile and Tank PB backgrounds show the form colour. When I downloaded the images, the backgrounds were transparent, I'm sure of it. How do I go about making the background of my PB's truly transparent? (Matching the background of the Overlapped PB?)
I saw this but it doesn't really match my scenario and I don't understand the solution.
UPDATE: Okay, I followed Tommy's advice, is this the right way to go about moving it along pbBackground in a timer constantly changing MissileX and MissileY? Currently this does nothing.
using (Graphics drawmissile = Graphics.FromImage(pbBackground.Image))
{
drawmissile.DrawImage(pbMissile.Image, new Point(MissileX,Convert.ToInt32(MissileY)));
}
PictureBox is opaque. And PictureBox is not efficient.
For making games, you should study Paint event which directly draws on your form.
Bitmap backgroundBitmap = new Bitmap("background");
Bitmap tankBitmap = new Bitmap("tank");
private void Form1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(backgroundBitmap, 0, 0);
e.Graphics.DrawImage(tankBitmap, 30, 30);
}
private void timer1_Tick(object sender, EventArgs e)
{
this.Invalidate(); //trigger Form1_Paint to draw next frame
}
Don't layer multiple PictureBox instances on top of each other. It will get very confusing, very quickly.
Instead, use one single PictureBox and use Paint to draw your images to it. In this way, you can have much more control over the graphics operations happening.
Have a look at this
private void DrawIt()
{
System.Drawing.Graphics graphics = this.CreateGraphics();
System.Drawing.Rectangle rectangle = new System.Drawing.Rectangle(
50, 50, 150, 150);
graphics.DrawEllipse(System.Drawing.Pens.Black, rectangle);
graphics.DrawRectangle(System.Drawing.Pens.Red, rectangle);
}
In this example they demonstrate how to draw shapes directly onto a Form. You would use your PictureBox there instead. You can also draw images.
There's lots of ways to draw shapes onto a form using a System.Drawing.Graphics object. Try taking a look at this question for a comparison.
Tommy's answer is right, however, if you're dead set on using pictureboxes (a bad idea), set the overlapping picturebox backgroundcolour to Transparent and the Form's Background to whatever image. TIL the Transparent BackColour just uses the form colour / image. Tommy actually has the right answer here, but this is what I did to fix my problem (the lazy way).
I have a problem on creating bitmap image out of my winform application.
Situation:
I have a UserControl named as "CanvasControl" that accepts OnPaint method acting as canvas for my Draw Pad application. Inside this user control I have a function "PrintCanvas()" that will create a screenshot image of the UserControl into PNG file. Below is the PrintCanvas() function:
public void PrintCanvas(string filename = "sample.png")
{
Graphics g = this.CreateGraphics();
//new bitmap object to save the image
Bitmap bmp = new Bitmap(this.Width, this.Height);
//Drawing control to the bitmap
this.DrawToBitmap(bmp, new Rectangle(0, 0, this.Width, this.Height));
bmp.Save(Application.StartupPath +
#"\ExperimentFiles\Experiment1" + filename, ImageFormat.Png);
bmp.Dispose();
}
This user control (CanvasControl) is called out inside my main form where user will draw something and have an option to save afterwards using a save button. The save button will call out the "PrintCanvas()" function of the UserControl.
I get the output image file as expected, but the problem is it was a blank image.
What I have tried so far:
To test that it is not a syntax issue, I tried to transfer the PrintCanvas() function into my main form and surprisingly I get an image of the whole main form on file but the UserControl is not visible there.
Is there any other setup i missed out to make a winform UserControl printable?
UPDATE: (DRAWING ROUTINES)
User control acting as canvas - code here
The code in the question gave a first hint but the code in the link showed the source of the problem: You use a 'wrong' instance of the Graphics object for drawing:
protected override void OnPaint(PaintEventArgs e)
{
// If there is an image and it has a location,
// paint it when the Form is repainted.
Graphics graphics = this.CreateGraphics();
..
This is one of the most common mistakes with winforms graphics! Never use CreateGraphics ! You always should draw onto the control surface with the Graphics object in a Paint or DrawXXX event. These events have a parameter e.Graphics which is the only one that can draw persistent graphics.
Persistent means that it will always be refreshed when necessary, not just when you trigger it. This is a nasty error because everything seems to work until you come upon a situation when an outside event makes redrawing necessary:
Minimizing and then maximizing the form
Moving it off the screen and back again
Calling DrawToBitmap
...
Note that all will only really work if you use the valid and current Graphics object from the PaintEventArgs e parameter.
So, the solution is simple:
protected override void OnPaint(PaintEventArgs e)
{
// If there is an image and it has a location,
// paint it when the Form is repainted.
Graphics graphics = e.Graphics(); // << === !!
..
But what is the CreateGraphics good for? It is only good for luring newbies into that error??
Not quite; here are some uses for it:
Drawing non-persistent graphics like a rubber-band rectangle or a special mouse cursor
Measuring text sizes without actually drawing it with a TextRenderer or the MeasureString method
Querying the screen or Bitmap resolution with Graphics.DpiX/Y
and probably some others I can't think of at the moment..
So for normal drawing onto controls always use the e.Grapahics object! You can pass it on to subroutines to make the code more structured, but do not try to cache it; it needs to be current!
i want to create a transparent form with png as background... which looks verymuch similar to this.
http://cdn.lo4d.com/t/screenshot/800/lili-usb-creator-3.jpg
so far i've used this code
protected override void OnPaintBackground(PaintEventArgs e)
{
e.Graphics.DrawImage(this.BackgroundImage, e.ClipRectangle);
}
but the problem is when moving the part below doesnt update!!
i tried to use
invalidate();
but it keeps on drawing the image over and over making the dropshadow part denser and denser.
is there anything i can do??
this one works great.not very neat but it works upto the mark.
http://www.codeproject.com/Articles/19213/An-Alpha-Channel-Composited-Windows-Form-with-Desi
I'm looking at being able to draw lines in code behind in C#, for a webpage created in Visual Studio. They will be just vertical lines but must be able to change size, depending on other variables.
I've got some code, as below:
using System.Drawing;
using System.Drawing.Imaging;
public partial class SpareFields : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Bitmap objBitmap;
Graphics objGraphics;
objBitmap = new Bitmap(400, 440);
objGraphics = Graphics.FromImage(objBitmap);
objGraphics.Clear(Color.White);
Pen p = new Pen(Color.Yellow, 0);
Rectangle rect = new Rectangle(600, 1500, 601, 2000);
objGraphics.DrawEllipse(p, rect);
objBitmap.Save(Response.OutputStream, ImageFormat.Gif);
//objBitmap.Save(Server.MapPath("x.jpg"), ImageFormat.Jpeg);
objBitmap.Dispose();
objGraphics.Dispose();
}
}
And so on. This is just at the start of the Page_Load - there's a lot of other non-graphics code in there. Trouble is, the rest of the page is being ignored and it's just drawing the graphics.
Also, I know the above is for an Ellipse (basically a quick test on some pie chart drawing). It'd be easy to adapt for a line, or a really thin rectangle.
Any idea how to draw, whilst still having the rest of the original page available?
To just draw some lines I'd use SVG, there are very few reasons not to use it for dynamic images, the big huge advantage for svg is you can change the image on the page/client via JS.
But if you really want bitmaps, there are many articles around the web discussing Dynamic Image, a Google for 'msdn dynamic image asp.net' should give you many, relevant articles with source.
The easiest way is to split this page in two:
1) your page outputs just it's html, including an <img> tag with a src attribute pointing to a new page
2) in that new page, use just that image generation code.