Is it possible to convert a indexed Bitmap to a unindexed without losing any quality?
I currently use this code to convert:
public Bitmap CreateNonIndexedImage(Image src)
{
Bitmap newBmp = new Bitmap(src.Width, src.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
using (Graphics gfx = Graphics.FromImage(newBmp))
{
gfx.DrawImage(src, 0, 0);
}
return newBmp;
}
Here is the indexed bitmap: http://puu.sh/6VO1N.png
And this is the converted image: http://puu.sh/6VO2Q.png
I need the unindexed to be exactly the same as the indexed but I don´t know what to do.
The image was resampled. That's normally a Good Thing, it helps to get rid of the dithering artifacts in the original image. But you don't like it so you have to turn interpolation off. You also should use the DrawImage() overload that prevents rescaling due to the resolution of the original image. Not actually a problem with the image you've got but it could be one with another. Thus:
public static Bitmap CreateNonIndexedImage(Image src) {
Bitmap newBmp = new Bitmap(src.Width, src.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
using (Graphics gfx = Graphics.FromImage(newBmp)) {
gfx.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.None;
gfx.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
gfx.DrawImage(src, new Rectangle(0, 0, src.Width, src.Height));
}
return newBmp;
}
Related
I cannot seem to programmatically create a colored bitmap to display in a PictureBox. The bitmap saves normally as a file, but is faded at the edges when displayed in a PictureBox. Here is simplified code used to create and display the Bitmap (in actual code, the bitmap generation is completely separate from the form, so forcing the bitmap size to match the picturebox size isn't possible):
Bitmap Bmp = new Bitmap(4, 4, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
using (Graphics gfx = Graphics.FromImage(Bmp))
using (SolidBrush brush = new SolidBrush(Color.BlueViolet))
{
gfx.FillRectangle(brush, 0, 0, 4, 4);
}
Then set the Image value on a PictureBox to the generated Bitmap:
pictureBox1.Image = Bmp;
Here is the resulting bitmap displayed in a 300x300 picturebox:
How do I set the Image on the PictureBox so that it displays the colored bitmap properly (full solid)?
EDIT: I am restricted to generating smaller source bitmaps, so upscaling into a PictureBox is unavoidable. The problem appears when the generated source bitmap is 4px or 100px square, so I believe these are relevant cases.
EDIT: The PictureBox scaling should be set to stretch or zoom for the issue to manifest. In this example case the 4x4 source bitmap is stretched to 300x300.
EDIT: The basic problem is PictureBox's inability to upscale small bitmaps into large controls. This is confusing because the Bitmap upscales nicely into a PictureBox.Background image. Unless you have a magic bullet that will fix the image upscaling problem, I think it might be best to go for clear and simple workarounds in your answer.
You are generating a 4x4 bitmap and it's being stretched. Specify the size to match the picture box instead:
int width = pictureBox1.Width;
int height = pictureBox1.Height;
var Bmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
using (Graphics gfx = Graphics.FromImage(Bmp))
using (var brush = new SolidBrush(Color.BlueViolet))
{
gfx.FillRectangle(brush, 0, 0, width, height);
}
pictureBox1.Image = Bmp;
You will need to turn anti-aliasing off. Also, since you are using one color for the whole picturebox, why not make the bitmap 1x1? If you need it 4x4, change the int the top of the example from 1 to 4.
int hw = 1;
Bitmap Bmp = new Bitmap(hw, hw,
System.Drawing.Imaging.PixelFormat.Format24bppRgb);
using (Graphics gfx = Graphics.FromImage(Bmp))
{
// Turn off anti-aliasing and draw an exact copy
gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.None;
gfx.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
using (SolidBrush brush = new SolidBrush(Color.BlueViolet))
{
gfx.FillRectangle(brush, 0, 0, hw, hw);
}
}
pictureBox1.Image = Bmp;
UPDATE
Since you are still having the same issue by setting the picturebox to the image, you will have to get the graphics object from the picturebox and draw directly on it.
The code is very similar.
using (Graphics gfx = Graphics.FromImage(pictureBox1.Image))
{
// Turn off anti-aliasing and draw an exact copy
gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.None;
gfx.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
using (SolidBrush brush = new SolidBrush(Color.BlueViolet))
{
gfx.FillRectangle(brush, 0, 0,
pictureBox11.Width - 1,
pictureBox11.Height - 1);
}
}
// Force the picturebox to redraw with the new image.
// You could also use pictureBox11.Refresh() to do the redraw.
pictureBox11.Invalidate();
I tried to test your code and the image were properly displayed.
But when i used this code:
Rectangle srcRect = New Rectangle(0, 0, Bmp.Width, Bmp.Height);
Rectangle dstRect = New Rectangle(0, 0, PictureBox1.Width, PictureBox1.Height);
g = PictureBox1.CreateGraphics;
g.DrawImage(Bmp, dstRect, srcRect, GraphicsUnit.Pixel);
g.Dispose();
I did get exactly your result. In order to fix it:
Rectangle srcRect = New Rectangle(0, 0, Bmp.Width - 1, Bmp.Height - 1);
Rectangle dstRect = New Rectangle(0, 0, PictureBox1.Width, PictureBox1.Height);
g = PictureBox1.CreateGraphics;
g.DrawImage(Bmp, dstRect, srcRect, GraphicsUnit.Pixel);
g.Dispose();
Edit:
So you have the bitmap and you want to stretch it. And the bitmap has ane solid color. Do this insted:
Color pixelColor = Bmp.GetPixel(0, 0);
PictureBox1.BackColor = pixelColor;
valter
I have a PictureBox with lots of transparent png's drawn into...
Now I'd like to save the content of this PictureBox to a file, but without the transparency.
How can I do this?
I have already tried to remove transparency from the Image like this, but it didn't work, I still got a transparent image after the save.
...
removeTransparency(pictureBox.Image).Save(saveFileDialog.FileName);
private Bitmap removeTransparency(Image transparentImage)
{
Bitmap src = new Bitmap(transparentImage);
Bitmap newImage = new Bitmap(src.Size.Width, src.Size.Height);
Graphics g = Graphics.FromImage(newImage);
g.DrawRectangle(new Pen(new SolidBrush(Color.White)), 0, 0, newImage.Width, newImage.Height);
g.DrawImage(src, 0, 0);
return newImage;
}
You may cycle through all pixel (please not using GetPixel/SetPixel) to change the color or you may create another bitmap with the same size, create a graphics context from the image, clear the image with your favorite background color and then draw your image on it (so transparent pixels simply will be replaced by the background color).
Example
Did you do something like this?
public static Bitmap Repaint(Bitmap source, Color backgroundColor)
{
Bitmap result = new Bitmap(source.Width, source.Height, PixelFormat.Format32bppArgb);
using (Graphics g = Graphics.FromImage(result))
{
g.Clear(backgroundColor);
g.DrawImage(source, new Rectangle(0, 0, source.Width, source.Height));
}
return result;
}
I'm trying to resize my image after copying it from the screen, and can't figure out how to do it. The tutorials I've been reading recommend using Graphics.DrawImage to resize the image, but when I run this code, it doesn't resize.
Bitmap b = new Bitmap(control.Width, control.Height);
Graphics g = Graphics.FromImage(b);
g.CopyFromScreen(control.Parent.RectangleToScreen(control.Bounds).X, control.Parent.RectangleToScreen(control.Bounds).Y, 0, 0, new Size(control.Bounds.Width, control.Bounds.Height), CopyPixelOperation.SourceCopy);
g.DrawImage(b, 0,0,newWidth, newHeight);
Any help would be appreciated, thanks!
Try this. Graphics won't "replace" the image when you use DrawImage - it draws the input image on its source, which is the same as the the image you're trying to draw to it.
Probably a more concise way to do this but.....
Bitmap b = new Bitmap(control.Width, control.Height);
using (Graphics g = Graphics.FromImage(b)) {
g.CopyFromScreen(control.Parent.RectangleToScreen(control.Bounds).X,
control.Parent.RectangleToScreen(control.Bounds).Y, 0, 0,
new Size(control.Bounds.Width, control.Bounds.Height),
CopyPixelOperation.SourceCopy);
}
Bitmap output = new Bitmap(newWidth, newHeight);
using (Graphics g = Graphics.FromImage(output)) {
g.DrawImage(b, 0,0,newWidth, newHeight);
}
Is there any reason why you can't just use a PictureBox control? That control takes care of stretching for you.
I'm using the following code to resize a tif. The tif has an alpha channel set for transparency. I'm trying to resize this image and honour the transparency but at the moment it's coming out with a black background. Any ideas?
public static void ResizeImage(string OriginalImagePath, string NewImagePath, int Width, int Height)
{
Size NewSize = new Size(Width, Height);
using (Image OriginalImage = Image.FromFile(OriginalImagePath))
{
//Graphics objects can not be created from bitmaps with an Indexed Pixel Format, use RGB instead.
PixelFormat Format = OriginalImage.PixelFormat;
if (Format.ToString().Contains("Indexed"))
Format = PixelFormat.Format24bppRgb;
using (Bitmap NewImage = new Bitmap(NewSize.Width, NewSize.Height, OriginalImage.PixelFormat))
{
using (Graphics Canvas = Graphics.FromImage(NewImage))
{
Canvas.SmoothingMode = SmoothingMode.AntiAlias;
Canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;
Canvas.PixelOffsetMode = PixelOffsetMode.HighQuality;
Canvas.DrawImage(OriginalImage, new Rectangle(new Point(0, 0), NewSize));
NewImage.Save(NewImagePath, OriginalImage.RawFormat);
}
}
}
}
}
Try this:
if (Format.ToString().Contains("Indexed"))
Format = PixelFormat.Format32bppArgb;
Format32bppArgb specifies an alpha channel in the pixel format.
And I think you meant to do this:
using (Bitmap NewImage = new Bitmap(NewSize.Width, NewSize.Height, Format))
EDIT:
Actually, try just forcing the pixel format on the NewImage to Format32bppArgb like so:
using (Bitmap NewImage = new Bitmap(NewSize.Width, NewSize.Height,
PixelFormat.Format32bppArgb))
Canvas.Clear(Color.Transparent)
before you blit.
I actually found out that due to the way the transparency is stored in the tiff format with photoshop it was better to create png's by automating photoshop and then crunching off the resulting png.
I need to convert a Bitmap from PixelFormat.Format32bppRgb to PixelFormat.Format32bppArgb.
I was hoping to use Bitmap.Clone, but it does not seem to be working.
Bitmap orig = new Bitmap("orig.bmp");
Bitmap clone = orig.Clone(new Rectangle(0,0,orig.Width,orig.Height), PixelFormat.Format24bppArgb);
If I run the above code and then check clone.PixelFormat it is set to PixelFormat.Format32bppRgb. What is going on/how do I convert the format?
Sloppy, not uncommon for GDI+. This fixes it:
Bitmap orig = new Bitmap(#"c:\temp\24bpp.bmp");
Bitmap clone = new Bitmap(orig.Width, orig.Height,
System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
using (Graphics gr = Graphics.FromImage(clone)) {
gr.DrawImage(orig, new Rectangle(0, 0, clone.Width, clone.Height));
}
// Dispose orig as necessary...
For some reason if you create a Bitmap from a file path, i.e. Bitmap bmp = new Bitmap("myimage.jpg");, and call Clone() on it, the returned Bitmap will not be converted.
However if you create another Bitmap from your old Bitmap, Clone() will work as intended.
Try something like this:
using (Bitmap oldBmp = new Bitmap("myimage.jpg"))
using (Bitmap newBmp = new Bitmap(oldBmp))
using (Bitmap targetBmp = newBmp.Clone(new Rectangle(0, 0, newBmp.Width, newBmp.Height), PixelFormat.Format32bppArgb))
{
// targetBmp is now in the desired format.
}
using (var bmp = new Bitmap(width, height, PixelFormat.Format24bppArgb))
using (var g = Graphics.FromImage(bmp)) {
g.DrawImage(..);
}
Should work like that. Maybe you want to set some parameters on g to define the interpolation mode for quality etc.