Draw text to image change bug [duplicate] - c#

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Closed 1 year ago.
I want to create program that draws text on image. For that purpose I used this method:
private static 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;
}
My problem is that I want to draw table in the image, so the table should look like:
I used this library for drawing table
And code looks like this method from above
var table = new ConsoleTable("one", "two", "three")
.AddRow("random text';", "random text", "random text")
.Configure(o => o.NumberAlignment = Alignment.Left)
.ToString();
DrawText(table, new Font("Verdana", 20), Color.Black, Color.White);
And i got this kind of image
Rows are really changed and it doesn't look like table above. I think method DrawText changed something but I don't know what exactly it is? So I need help. Sorry for my bad English

If you don't need Verdana (which isn't a monospaced font), you should be able to fix this by slightly altering your call to DrawText like so:
DrawText(table, new Font(FontFamily.GenericMonospace, 20), Color.Black, Color.White);
I'm not actually super familiar with working with fonts, so using FontFamily.GenericMonospace is sort of my best guess. You should be able to use others though. Wikipedia has a list of them.

Related

Invert Crop from (Cut hole into) Image

Everywhere I look online, I see people posting on how to successfully crop an image. However, I want to 'crop'/ clear a hole out of an image. I want to keep the original image, but crop out a rectangle
As you can see in the image above, I have "cropped" out the kittens face. I maintained the original image, but removed only part of it. I cannot figure out how to do that.
Assuming you want to replace the original pixel colors with transparency you run into a small problem: You can't draw or fill with transparency in GDI+.
But you can use Graphics.Clear(Color.Transparent).
To do that you restrict the region where the Graphics object will draw. Here we can use the simple cropping rectangle but you can clear more complex shapes using a GraphicsPath..
Example using a bitmap bmp:
using (Graphics g = Graphics.FromImage(bmp))
{
Rectangle crop = new Rectangle(222,222,55,55);
g.SetClip(crop);
g.Clear(Color.Transparent);
}
bmp.Save(somefilename, ImageFormat.Png);
Setting your Graphics object's CompositingMode property to CompositingMode.SourceCopy will allow your drawing operations to replace the alpha value instead of proportionally opacifying it:
public static void TestDrawTransparent()
{
//This code will, successfully, draw something transparent overwriting an opaque area.
//More precisely, it creates a 100*100 fully-opaque red square with a 50*50 semi-transparent center.
using(Bitmap bmp = new Bitmap(100, 100, PixelFormat.Format32bppArgb))
{
using(Graphics g = Graphics.FromImage(bmp))
using(Brush opaqueRedBrush = new SolidBrush(Color.FromArgb(255, 255, 0, 0)))
using(Brush semiRedBrush = new SolidBrush(Color.FromArgb(128, 255, 0, 0)))
{
g.Clear(Color.Transparent);
Rectangle bigRect = new Rectangle(0, 0, 100, 100);
Rectangle smallRect = new Rectangle(25, 25, 50, 50);
g.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
g.FillRectangle(opaqueRedBrush, bigRect);
g.FillRectangle(semiRedBrush, smallRect);
}
bmp.Save(#"C:\FilePath\TestDrawTransparent.png", ImageFormat.Png);
}
}
In this code, I first draw a fully-opaque red square, then a semi-transparent red square "over" it. The result is a semi-transparent "hole" in the square:
And on a black background:
A zero-opacity brush works just as well, leaving a clear hole through the image (I checked).
With that in mind, you should be able to crop any shapes you want, simply by filling them with a zero-opacity brush.

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
}

Ultrabutton not displaying unicode character in text property while running application

I'm trying to display the text property of a UltraButton to this unicode character- ▼ .
I've tried to copy this from the Character Map and also tried something like-
button1.Text = "\u2129"
The problem is both of them show the arrows in the designer mode in VS, but when I run the application, it shows an unrecognised symbol. I've gone through this link and this link, but the arrows only show up in the designer view, not while running the application. Why is this happening. Also, I've set the Font name to 'Arial Unicode MS'
I'm guessing the issue you are experiencing is unique to the UltraButton. From the looks of the image you just posted, you could probably get away with just using a standard Windows From Button. If you can, just open your ClassName.Designer.cs and find where your button text is being set. Copy the actual character into the text string:
this.YourButton.Text = "▼";
This shows up correctly in both the designer and when running the application.
If you really don't want to use a standard Windows Forms Button, you could always go about converting your text to an image and adding the image to the button. Would look something like this:
string text = "▼";
Font font = new Font("Arial Unicode MS", 12f);
Image img = new Bitmap(1, 1);
Graphics drawing = Graphics.FromImage(img);
SizeF textsize = drawing.MeasureString(text, font);
img.Dispose();
drawing.Dispose();
img = new Bitmap((int) textsize.Width, (int)textsize.Height);
drawing = Graphics.FromImage(img);
drawing.Clear(YourButton.BackColor);
Brush textBrush = new SolidBrush(Color.Black);
drawing.DrawString(text, font, textBrush, 0, 0);
drawing.Save();
textBrush.Dispose();
drawing.Dispose();
YourButton.Text = "";
YourButton.Image = img;

Bitmap Text Background and HorizontalAlignment

I am overlaying text to a bitmap as shown below, I need to be able to set a background colour behind the text and also set the HorizontalAlignment (i.e left/right/centre), can anyone advise me how this can be done. Also note the text size can vary.
Thanks.
Bitmap frameBitmap = new Bitmap(streamFrameWidth, streamFrameHeight,
streamFrameWidth * 3,
System.Drawing.Imaging.PixelFormat.Format24bppRgb, pFrame);
using (Graphics g = Graphics.FromImage(frameBitmap))
{
// Create font and brush.
Font drawFont = new Font("Arial", 12, FontStyle.Bold);
SolidBrush drawBrush = new SolidBrush(Color.Black);
// Create point for upper-left corner of drawing.
PointF drawPoint = new PointF(10.0F, 40.0F);
//HorizontalAlignment.
// draw the text
g.DrawString(overlayText, drawFont, drawBrush, drawPoint);
}
You can control the alignment of the drawn text by using the StringFormat parameter of the DrawString method.
Example
MSDN
You probably need TextRenderer.MeasureText.
It returns the size of the text to be displayed. Combining the size of the text with the size of the Bitmap, you can work out the appropriate location of the text based upon the required HorizontalAlignment.
Once you know the bounds (size and location) of the text, you can simply paint a color to those bounds to implement a background colour before drawing the text on top.

TextRenderer.DrawText in Bitmap vs OnPaintBackground

If I use TextRenderer.DrawText() using the Graphics object provided in the OnPaintBackground my text looks perfect. If I create my own Bitmap and use the Graphics object obtained from my Bitmap my text looks terrible. It looks like it is anti-aliasing the text using black, not the bitmap's background color. I can avoid this problem if I use Graphics.DrawString(), but this method has horrible kerning problems. What should I do? How can I get TextRenderer.DrawText() to anti-alias properly using the Bitmap's contents?
Looks terrible:
Bitmap bmp = new Bitmap(100, 100, PixelFormat.Format32bppArgb);
using (Graphics g = Graphics.FromImage(bmp))
{
g.Clear(Color.Red);
TextFormatFlags tf = TextFormatFlags.Left;
TextRenderer.DrawText(g, #"C:\Development\Testing\blag", font, clip, Color.White,
Color.Transparent, tf);
}
Looks good, but I want to render this onto a bitmap, NOT onto the control's surface:
protected override void OnPaintBackground(PaintEventArgs e)
{
e.Graphics.Clear(Color.Red);
TextFormatFlags tf = TextFormatFlags.Left;
TextRenderer.DrawText(e.Graphics, #"C:\Development\Testing\blag", font, clip,
Color.White, Color.Transparent, tf);
}
What is the difference?
The answer is not to use TextRenderer. TextRenderer is a wrapper for the GDI (not GDI+) implementation of text rendering, which has lots of features, but doesn't interoperate well with in-memory DCs as you have discovered.
Use Graphics.DrawString & Graphics.MeasureString, but remember to pass it StringFormat.GenericTypographic to get accurate size and positioning.
The reason TextRenderer was introduced initially was that GDI+ didn't support all the complex scripts that GDI's Uniscribe engine did. Over time however GDI+ support for complex scripts has been expanded, and these days there aren't any good reasons left to use TextRenderer (it's not even the faster of the two anymore, in fact quite the opposite it appears).
Really, though, unless you are running into serious, measurable performance issues just use Graphics.DrawString.
I believe the problem is that the clear type text rendering doesn't work if the background is transparent. A few possible solutions.
Option 1. Fill the background of your bitmap with a color.
If you do this (as Tim Robinson did above in his code example by using g.Clear(Color.Red)) clear type will do the right thing. But your bitmap won't be completely transparent which might not be acceptable. If you use Graphics.MeasureText, you can fill just the rectangle around your text, if you like.
Option 2. Set TextRenderingHint = TextRenderingHintAntiAliasGridFit
This appears to turn off clear type. The text will be rendered at a lower quality than clear type on a background, but much better than the mess clear type on no background creates.
Option 3. Fill the text rectangle with white, draw the text and then find all the non-text pixels and put them back to transparent.
using (Bitmap bmp = new Bitmap(someWidth, someHeight))
{
using (Graphics g = Graphics.FromImage(bmp))
{
// figure out where our text will go
Point textPoint = new Point(someX, someY);
Size textSize = g.MeasureString(someText, someFont).ToSize();
Rectangle textRect = new Rectangle(textPoint, textSize);
// fill that rect with white
g.FillRectangle(Brushes.White, textRect);
// draw the text
g.DrawString(someText, someFont, Brushes.Black, textPoint);
// set any pure white pixels back to transparent
for (int x = textRect.Left; x <= textRect.Left + textRect.Width; x++)
{
for (int y = textRect.Top; y <= textRect.Top + textRect.Height; y++)
{
Color c = bmp.GetPixel(x, y);
if (c.A == 255 && c.R == 255 && c.G == 255 && c.B == 255)
{
bmp.SetPixel(x, y, Color.Transparent);
}
}
}
}
}
I know, it's a horrible hack, but it appears to work.
The answer is to use a BuffersGraphicsContext. This is the same system that .NET uses internally when you set the ControlStyles.OptimizedDoubleBuffer style on a control.
See http://msdn.microsoft.com/en-us/library/b367a457.aspx for more information about double buffering in .NET.
Another possible solution: Draw the whole thing to the screen, bitmap with text on top, and then write some code to 'screen capture' that portion of the screen. Not practical in all cases but you're right, DrawString creates weird text and DrawText onto a bitmap looks horrible.
If your bitmap is not the same size as your display area, it might just be a resizing issue, where .NET scales the bitmap to the display size and you get funny looking text.
Can you test with a bitmap created at the same size as your display area?
Can you post the smallest program that suffers from this problem? I can't reproduce it like this -- the antialiasing looks fine:
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;
public class Program
{
public static void Main()
{
Bitmap bmp = new Bitmap(100, 100, PixelFormat.Format32bppArgb);
using (Font font = new Font("Arial", 10, GraphicsUnit.Point))
using (Graphics g = Graphics.FromImage(bmp))
{
Rectangle clip = Rectangle.FromLTRB(0, 0, 100, 100);
g.Clear(Color.Red);
TextFormatFlags tf = TextFormatFlags.Left;
TextRenderer.DrawText(g, #"C:\Development\Testing\blag", font, clip, Color.White, Color.Transparent, tf);
}
Form form = new Form();
form.BackgroundImage = bmp;
Application.Run(form);
}
}

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