Develop Reference

Converting Scanned PDF's to an Image

I'm able to scan a JPG image using Tesseract, I'm able to scan a regular PDF using ITextSharp and get the text from those. But I can't find a way to either get the text from a scanned PDF with a .PDF extension, or convert a PDF to an image so I can then scan it with Tesseract. Are there any options that I'm missing? Thanks!

Assuming that you have scanned the PDF document. Secondly assuming you have only text in the PDF document. You can generate an image from text from the following method
private Image DrawText(String text, Font font, Color textColor, Color backColor)
{
//first, create a dummy bitmap just to get a graphics object
Image img = new Bitmap(1, 1);
Graphics drawing = Graphics.FromImage(img);
//measure the string to see how big the image needs to be
SizeF textSize = drawing.MeasureString(text, font);
//free up the dummy image and old graphics object
img.Dispose();
drawing.Dispose();
//create a new image of the right size
img = new Bitmap((int) textSize.Width, (int)textSize.Height);
drawing = Graphics.FromImage(img);
//paint the background
drawing.Clear(backColor);
//create a brush for the text
Brush textBrush = new SolidBrush(textColor);
drawing.DrawString(text, font, textBrush, 0, 0);
drawing.Save();
textBrush.Dispose();
drawing.Dispose();
return img;
}
Reference: How to generate an image from text on fly at runtime

Dynamically generated Bitmap image with aligned data in it

I'm developing an Winforms application to be used for Led displays. The Led display is size 64x32. I created a test bitmap image with 4 cells size 64x16, so I can output it it to the LED display.
When the user enters 4 numbers in the input form, those Strings are then converted to Bitmap Image and placed inside the cells. I somehow got it to work with this method; It edits the same bitmap image, inserts the numbers, and saves it into a new bmp (or am I wrong?).
public static Bitmap Convert_Text_to_Image(string txt, string fontname, int fontsize)
{
//creating bitmap image
Bitmap bmp = new Bitmap("cells.bmp");
//FromImage method creates a new Graphics from the specified Image.
Graphics graphics = Graphics.FromImage(bmp);
// Create the Font object for the image text drawing.
Font font = new Font(fontname, fontsize);
// Instantiating object of Bitmap image again with the correct size for the text and font.
SizeF stringSize = graphics.MeasureString(txt, font);
bmp = new Bitmap(bmp, (int)stringSize.Width, (int)stringSize.Height);
graphics = Graphics.FromImage(bmp);
//Draw Specified text with specified format
graphics.DrawString(txt, font, Brushes.Red, 0, 0);
font.Dispose();
graphics.Flush();
graphics.Dispose();
bmp.Save("cells2.bmp", System.Drawing.Imaging.ImageFormat.Bmp);
return bmp; //return Bitmap Image
}
The output in the PictureBox is This
Now I've created myself multiple problems with the alignment, since I just pasted "bmp numbers" directly onto the "bmp cells"... is there a function of "mapping" the numbers correctly inside the cells, depending if its a single-digit or a two-digit number?
I'm pretty certain there's a way easier way to do all of this, maybe with the DataGridView? I only started using C#, any help would be appreciated.
The image "cells.bmp" is just a test image i created in Paint (xd), rather than that, I'm trying to write a function that will create the Bitmap cells through code
if (want_x_number_cells) {
//create bmp with appropriate number of cells
}

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.

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.

Saving System.Drawing.Graphics to a png or bmp

I have a Graphics object that I've drawn on the screen and I need to save it to a png or bmp file. Graphics doesn't seem to support that directly, but it must be possible somehow.
What are the steps?

Here is the code:
Bitmap bitmap = new Bitmap(Convert.ToInt32(1024), Convert.ToInt32(1024), System.Drawing.Imaging.PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(bitmap);
// Add drawing commands here
g.Clear(Color.Green);
bitmap.Save(#"C:\Users\johndoe\test.png", ImageFormat.Png);
If your Graphics is on a form, you can use this:
private void DrawImagePointF(PaintEventArgs e)
{
... Above code goes here ...
e.Graphics.DrawImage(bitmap, 0, 0);
}
In addition, to save on a web page, you could use this:
MemoryStream memoryStream = new MemoryStream();
bitmap.Save(memoryStream, ImageFormat.Png);
var pngData = memoryStream.ToArray();
<img src="data:image/png;base64,#(Convert.ToBase64String(pngData))"/>
Graphics objects are a GDI+ drawing surface. They must have an attached device context to draw on ie either a form or an image.

Copy it to a Bitmap and then call the bitmap's Save method.
Note that if you're literally drawing to the screen (by grabbing the screen's device context), then the only way to save what you just drew to the screen is to reverse the process by drawing from the screen to a Bitmap. This is possible, but it would obviously be a lot easier to just draw directly to a Bitmap (using the same code you use to draw to the screen).

Try this, works fine for me...
private void SaveControlImage(Control ctr)
{
try
{
var imagePath = #"C:\Image.png";
Image bmp = new Bitmap(ctr.Width, ctr.Height);
var gg = Graphics.FromImage(bmp);
var rect = ctr.RectangleToScreen(ctr.ClientRectangle);
gg.CopyFromScreen(rect.Location, Point.Empty, ctr.Size);
bmp.Save(imagePath);
Process.Start(imagePath);
}
catch (Exception)
{
//
}
}

Graphics graph = CreateGraphics();
Bitmap bmpPicture = new Bitmap("filename.bmp");
graph.DrawImage(bmpPicture, width, height);

You are likely drawing either to an image or on a control. If on image use
Image.Save("myfile.png",ImageFormat.Png)
If drawing on control use Control.DrawToBitmap() and then save the returned image as above.
Thanks for the correction - I wasn't aware you can draw directly to the screen.