Develop Reference

How to get Graphic's object with out using a control in c# using GDI+?

I need to create a drawing with a circle and text embeded to it .This drawing is outputted as Image file (Jpeg/Jpg/svg/Png) using c# GDI+ .
Since i dont want to display the UI directly on a form ,how do i get the graphic's object to start drawing.
Thanks in advance.

You can create a new Bitmap passing the size for the image:
using (Bitmap myBitmap = new Bitmap(100, 100)) {
using (Graphics g = Graphics.FromImage(myBitmap)) {
// do your drawing here
}
myBitmap.Save(#"C:\path\for\image.bmp");
}
Optionally you can set the ImageFormat for the image when saving
myBitmap.Save(#"C:\path\for\image.png", ImageFormat.Png);

You create a Bitmap, and get the graphics object from it to draw on:
Bitmap myBitmap = new Bitmap(#"C:\MyImg.bmp");
Graphics g = Graphics.FromImage(myBitmap);
Note that the Bitmap does not need to be created on disk, it can be created in memory too!

Image Overlaping in Windows Phone 8.1

I am creating a Windows Phone Application, in which i require an image (let it be image1).
I have 100 other images, what i want is to overlap each image, to the image1 when needed.
(Note: I want to save the image after editing)
What will be the possible way to create this in Windows Phone.
I am familiar with C# in WPForms, and i used this code before...
//In this code i am drawing 2.png on 1.png
string imageFilePath = #"D:\1.png";
Bitmap bitmap = (Bitmap)Image.FromFile(imageFilePath);//load the image file
string image = #"D:\2.png";
Bitmap bitmap2 = (Bitmap)Image.FromFile(image);//load the image file
using (Graphics graphics = Graphics.FromImage(bitmap))
{
graphics.DrawImageUnscaled(bitmap2, 5, 5);
}

Try This:
WriteableBitmap bmpCurrentScreenImage = new WriteableBitmap((int)this.ActualWidth, (int)this.ActualHeight);
bmpCurrentScreenImage.Render(LayoutRoot, new MatrixTransform());
bmpCurrentScreenImage.Invalidate();
Save Bitmap bmpCurrentScreenImage where You want to save.

Is there a way to overlay or merge a Drawing.Bitmap and a DrawingImage

In a windows forms application, I have as input a Drawing.Bitmap and a DrawingImage. I need to overlay them and put there output in a Controls.Image. How can I do this?

It doesn't matter if you use Image object or Bitmap object, The Drawing.Image is abstract class and Drawing.Bitmap inherited from it. to
draw image over image, get the graphics object from the base image and then use Graphics.DrawImage which accept parameter of type Image.
So you have two images here, one should be printed "overlay" over the other image:
System.Drawing.Image primaryImage = Image.FromFile(#"Your file path");//or resource..
using (Graphics graphics = Graphics.FromImage(primaryImage))//get the underlying graphics object from the image.
{
using (Bitmap overlayImage = new Bitmap(primaryImage.Width, primaryImage.Hieght,
System.Drawing.Imaging.PixelFormat.Format32bppArgb)//or your overlay image from file or resource...
{
graphics.DrawImage(overlayImage, new Point(0, 0));//this will draw the overlay image over the base image at (0, 0) coordination.
}
}
Control.Image = primaryImage;
Not that if the overlay image doesn't have some transparent, and its size is equals or larger than the base image, it will overlap the other image completely, so you the overlay image must have some opacity.

I realize it has been awhile, but the answers here weren't quite working for me. A little tweaking, though made them work fine. For what it is worth, here is my final version.
SCENARIO:
background image is RGB 24
overlay image is ARGB 32 with alpha channel already set properly.
images created from a memory stream
PROBLEM:
Creating the overlay image from the memory stream assumed I meant: Format32bppRgb
But what is needed is Format32bppArgb since the transparency is already in place..
SOLUTION:
pictureBox1.Image = MergeImages( backgroundImage, overlayImage);
using System.Drawing;
using System.Drawing.Imaging;
// ...
private Image MergeImages(Image backgroundImage,
Image overlayImage)
{
Image theResult = backgroundImage;
if (null != overlayImage)
{
Image theOverlay = overlayImage;
if (PixelFormat.Format32bppArgb != overlayImage.PixelFormat)
{
theOverlay = new Bitmap(overlayImage.Width,
overlayImage.Height,
PixelFormat.Format32bppArgb);
using (Graphics graphics = Graphics.FromImage(theOverlay))
{
graphics.DrawImage(overlayImage,
new Rectangle(0, 0, theOverlay.Width, theOverlay.Height),
new Rectangle(0, 0, overlayImage.Width, overlayImage.Height),
GraphicsUnit.Pixel);
}
((Bitmap)theOverlay).MakeTransparent();
}
using (Graphics graphics = Graphics.FromImage(theResult))
{
graphics.DrawImage(theOverlay,
new Rectangle(0, 0, theResult.Width, theResult.Height),
new Rectangle(0, 0, theOverlay.Width, theOverlay.Height),
GraphicsUnit.Pixel);
}
}
return theResult;
}

Icon to Image - transparency issue

I'm trying to build a treeview like file list in a richtext box.
It should look like an explorer treeview. My code is able to get an resize the icon, but the transparency is missing (light gray background instead of transparency). What do I need to change here? Is the Image format wrong?
Is there a better way to add an image to a richtextbox?
// Get file info
FileInfo f = new FileInfo("myfile.name");
// Get icon for fileinfo
Icon ico = Icon.ExtractAssociatedIcon(f);
// Convert icon to bitmap
Bitmap bm = ico.ToBitmap();
// create new image with desired size
Bitmap img = new Bitmap(16,16,PixelFormat.Frmat32bpRgb);
// Create graphics with desired sized image
Graphics g = Graphics.FormImage(img);
// set interpolation mode
g.InterpolationMode = InterpolationMode.HighQualityBiCubic;
// draw/resize image
g.DrawImage(bm, new Rectangle(0,0,16,16), new Rectangle(0, 0, bm.Width, bm,Height), GraphicalUnit.Pixel);
// Paste to clipboard
Clipboard.SetImage(bm);
// Paste in RichtextBox
rtb.Paste();
Example:
Edit:
I've figured out that the image is transparent, but using Clipboard.SetImage() doesn't publish it as transparent image.
Any ideas why and what can I do to fix it? Do I need to switch to a differn textbox control?

I've had some luck going through Graphics.
Bitmap b = new Bitmap(pbAssetLoaded.Width, pbAssetLoaded.Height);
using (Graphics g = Graphics.FromImage(b))
{
g.DrawIcon(SystemIcons.Information, 0, 0);
}
This draws the icon with transparency to the Bitmap.

Try
img.MakeTransparent();
after you contruct it.
Note that this will change your PixelFormat to Format32bppArgb.

Edit multipage TIFF image using System.Drawing

I'm tring to edit multipage tiff by creating Graphics from the image, but i encountered the error message: “A Graphics object cannot be created from an image that has an indexed pixel format.”
How can i edit multipage tiff?

I wrote something to extract single pages from a multipage tiff file.
// Load as Bitmap
using (Bitmap bmp = new Bitmap(file))
{
// Get pages in bitmap
int frames = bmp.GetFrameCount(System.Drawing.Imaging.FrameDimension.Page);
bmp.SelectActiveFrame(System.Drawing.Imaging.FrameDimension.Page, tiffpage);
if (bmp.PixelFormat != PixelFormat.Format1bppIndexed)
{
using (Bitmap bmp2 = new Bitmap(bmp.Width, bmp.Height))
{
bmp2.Palette = bmp.Palette;
bmp2.SetResolution(bmp.HorizontalResolution, bmp.VerticalResolution);
// create graphics object for new bitmap
using (Graphics g = Graphics.FromImage(bmp2))
{
// copy current page into new bitmap
g.DrawImageUnscaled(bmp, 0, 0);
// do whatever you migth to do
...
}
}
}
}
The snippet loads the tif file and extracts the one page (number in variable tiffpage) into a new bitmap. This is not indexed and an graphics object can be created.

The error : A Graphics object cannot be created from an image that has an indexed pixel format.
...has nothing to do with it being a multipage TIFF. An indexed image format means it has a palette of colours, e.g. it's a 256-colour image. A 1-bit image (B&W) would also count as having a palette of 2 colours.
You can't perform Graphics operations on images that use a palette, they'd need to be converted to 15-bit or more colour depth first.

Here is a link to a CodeProject sample that includes code for converting a TIFF file to a normal Bitmap, which you can then work with like any other Bitmap:
http://www.codeproject.com/KB/GDI-plus/BitonalImageConverter.aspx

I once wrote little utility to create encrypted pdfs from tiff images. Here is a piece of code to get pages from tiff image:
var bm= new System.Drawing.Bitmap('tif path');
var total = bm.GetFrameCount(System.Drawing.Imaging.FrameDimension.Page);
for(var x=0;x<total;x++)
{
bm.SelectActiveFrame(System.Drawing.Imaging.FrameDimension.Page,x);
var img=Image.GetInstance(bm,null,false);
//do what ever you want with img object
}