I have this code to resize an image but the image doesn't look so good:
public Bitmap ProportionallyResizeBitmap(Bitmap src, int maxWidth, int maxHeight)
{
// original dimensions
int w = src.Width;
int h = src.Height;
// Longest and shortest dimension
int longestDimension = (w > h) ? w : h;
int shortestDimension = (w < h) ? w : h;
// propotionality
float factor = ((float)longestDimension) / shortestDimension;
// default width is greater than height
double newWidth = maxWidth;
double newHeight = maxWidth / factor;
// if height greater than width recalculate
if (w < h)
{
newWidth = maxHeight / factor;
newHeight = maxHeight;
}
// Create new Bitmap at new dimensions
Bitmap result = new Bitmap((int)newWidth, (int)newHeight);
using (Graphics g = Graphics.FromImage((System.Drawing.Image)result))
g.DrawImage(src, 0, 0, (int)newWidth, (int)newHeight);
return result;
}
Try setting the InterpolationMode of the graphics object to some value such as HighQualityBicubic. This should ensure that resize/scaled image looks much better than the "default".
So, in the code you have posted, instead of doing:
// Create new Bitmap at new dimensions
Bitmap result = new Bitmap((int)newWidth, (int)newHeight);
using (Graphics g = Graphics.FromImage((System.Drawing.Image)result))
g.DrawImage(src, 0, 0, (int)newWidth, (int)newHeight);
return result;
Try doing this instead:
// Create new Bitmap at new dimensions
Bitmap result = new Bitmap((int)newWidth, (int)newHeight);
using (Graphics g = Graphics.FromImage((System.Drawing.Image)result))
{
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.DrawImage(src, 0, 0, (int)newWidth, (int)newHeight);
}
return result;
(Note the line setting the InterpolationMode property to one of the InterpolationMode enumeration's values).
Please see this link:
How to: Use Interpolation Mode to Control Image Quality During Scaling
For further information on controlling the quality of an image when resizing/scaling.
Also see this CodeProject article:
Resizing a Photographic image with GDI+ for .NET
For information of the different visual effects the various InterpolationMode enumeration settings will have on an image. (About two-thirds of the way down the article, under the section entitled, "One last thing...").
If you need an on-the-fly resize I suggest you to try an HttpHandler I write recently, I've posted the code on my blog (sorry, but is in italian).
With some modifies you can use the code also for save the transformed image on the disk.
Related
I have an Image which I want to crop. I already know that my required content is in the lower part of the image so how can I automatically crop it using Rectangle ?
I tried to use this Code (Below) to crop but it didn't help. I haven't used Rectangle much so please guide me.
private Bitmap cropImage(Bitmap img)
{
int height= img.Height / 2;
Rectangle CropArea = new Rectangle(100,height, 1400, 900);
Bitmap bmpCrop = img.Clone(CropArea, img.PixelFormat);
return bmpCrop;
}
the cropped image turned out fine but it's hardcoded. I need to make it dynamic so it gives same result for different images
Thanks #John for your answer. this code will cut 50% of the image and give your it's lower half:
private Bitmap cropImage(Bitmap img)
{
int height= img.Height / 2;
int newWidth = img.Width -100;
int newHeight = img.Height - height;
Rectangle CropArea = new Rectangle(100,height,newWidth,newHeight);
Bitmap bmpCrop = img.Clone(CropArea, img.PixelFormat);
return bmpCrop;
}
I'm using C# to scale and rotate an image with a transparent background, then using JavaScript to add it to a Google Maps API map, but once it's scaled and rotated, the edges of the image get blurred, and it becomes hard to see, especially over water.
Here is my original 300x300 image:
And here is an example of one of the output images at 100x100 (SizeInt = 100):
Before you get confused as to the background colour, the image is projected onto a map where the water is a similar colour to the image.
You can see some slight ghosting around the edges of the image.
Once it's scaled down further (to it's required scale):
It's almost unnoticeable...
I'm still relatively new to C#, but I've tried loading SVGs directly onto the map with JavaScript (icon: "some/SVG/file.svg"), but that causes serious performance problems, as there are up to 1,000 icons on the map at any given time, making the map unusable when using SVG files, so I have to use image files.
The images need to be sharp and not blurred around the edges. Here is the code used to generate the images, forgive any sloppy code, I'm still somewhat new to C#:
Here is the code used to scale the image:
The image needs to be rotated in a full circle (rounded to 5 degrees), hence the loop from 0 to 361.
private void BuildIcons(string dir)
{
int SizeInt = 30;
// Get the content path
var ContentPath = dir;
// Get the original image
Bitmap OriginalImage = new Bitmap(ContentPath + "base.png");
#region Resize image
// New size
Size size = new Size(SizeInt, SizeInt);
// New height/width temp vars
int newWidth;
int newHeight;
// Aspect ratio preservation
int originalWidth = OriginalImage.Width;
int originalHeight = OriginalImage.Height;
float percentWidth = (float)size.Width / (float)originalWidth;
float percentHeight = (float)size.Height / (float)originalHeight;
float percent = percentHeight < percentWidth ? percentHeight : percentWidth;
newWidth = (int)(originalWidth * percent);
newHeight = (int)(originalHeight * percent);
// Generate the new image
Image ResizedImage = new Bitmap(newWidth, newHeight);
using (Graphics graphicsHandle = Graphics.FromImage(ResizedImage))
{
graphicsHandle.SmoothingMode = SmoothingMode.HighQuality;
graphicsHandle.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphicsHandle.PixelOffsetMode = PixelOffsetMode.HighQuality;
graphicsHandle.DrawImage(OriginalImage, 0, 0, newWidth, newHeight);
}
#endregion
int maxside = SizeInt;
#region Image rotation
// Generate images
for (int i = 0; i < 361; i += 5)
{
// New empty bitmap to hold rotated images
Bitmap ReturnBitmap = new Bitmap(maxside, maxside);
// Graphics object from the empty bitmap
// Normal
Graphics Gfx = Graphics.FromImage(ReturnBitmap);
Gfx.SmoothingMode = SmoothingMode.HighQuality;
Gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;
Gfx.PixelOffsetMode = PixelOffsetMode.HighQuality;
// Move rotation point to center of image
Gfx.TranslateTransform(
(float)ResizedImage.Width / 2,
(float)ResizedImage.Height / 2
);
// Rotate
Gfx.RotateTransform(i);
// Move image back
Gfx.TranslateTransform(
-(float)ResizedImage.Width / 2,
-(float)ResizedImage.Height / 2
);
// draw original in image onto graphics object
Gfx.DrawImage(ResizedImage, new Point(0, 0));
// Save the image
ReturnBitmap.Save(ContentPath + i.ToString() + ".png");
// Clean up
ReturnBitmap.Dispose();
Gfx.Dispose();
}
#endregion
// Clean up
ResizedImage.Dispose();
OriginalImage.Dispose();
}
Any suggestions?
I am loading images onto an excel page, once done this excel is around 48,284 KB This is to large and affects the download speed and is not efficient to what we are trying to achieve.
I am trying to reduce this Excel file size as much as possible and think that reducing the image sizes would do the trick as the excel file without images is around 1000 kb.
This is what i have tried so far with no affect:
public Image ReduceImageSize(Image img)
{
float iwidth = 150;
float iheight = 150;
var brush = new SolidBrush(Color.Black);
var Resizedimage = new Bitmap(img);
float scale = Math.Min(iwidth / Resizedimage.Width, iheight / Resizedimage.Height);
var graph = Graphics.FromImage(Resizedimage);
graph.InterpolationMode = InterpolationMode.Low;
graph.CompositingQuality = CompositingQuality.Default;
graph.SmoothingMode = SmoothingMode.None;
var scaleWidth = (int)(Resizedimage.Width * scale);
var scaleHeight = (int)(Resizedimage.Height * scale);
graph.FillRectangle(brush, new RectangleF(0, 0, iwidth, iheight));
graph.DrawImage(Resizedimage, new Rectangle(((int)iwidth - scaleWidth) / 2, ((int)iheight - scaleHeight) / 2, scaleWidth, scaleHeight));
return Resizedimage;
}
At this point i'm looking for any way to reduce the size if it involves losing some quality or reducing the images dimensions.
Please help.
You made Resizedimage the same size as img.
Use the following code to fix the result image size:
var Resizedimage = new Bitmap(iwidth,iheight);
An example resizing an image keeping the aspect ratio:
Image img = Image.FromFile(#"c:\temp\1.jpg");
Bitmap resizedImg = new Bitmap(150, 150);
double ratioX = (double)resizedImg.Width / (double)img.Width;
double ratioY = (double)resizedImg.Height / (double)img.Height;
double ratio = ratioX < ratioY ? ratioX : ratioY;
int newHeight = Convert.ToInt32(img.Height * ratio);
int newWidth = Convert.ToInt32(img.Width * ratio);
using (Graphics g = Graphics.FromImage(resizedImg))
{
g.DrawImage(img, 0, 0, newWidth, newHeight);
}
resizedImg.Save(#"c:\temp\2.jpg");
It's embarrassing to ask this question but can't find an answer.
I tried this in vain.
Image resultImage = new Bitmap(image1.Width, image1.Height, PixelFormat.Format24bppRgb);
using (Graphics grp = Graphics.FromImage(resultImage))
{
grp.FillRectangle(
Brushes.White, 0, 0, image1.Width, image1.Height);
resultImage = new Bitmap(image1.Width, image1.Height, grp);
}
I basically want to fill a 1024x1024 RGB bitmap image with white in C#. How can I do that?
You almost had it:
private Bitmap DrawFilledRectangle(int x, int y)
{
Bitmap bmp = new Bitmap(x, y);
using (Graphics graph = Graphics.FromImage(bmp))
{
Rectangle ImageSize = new Rectangle(0,0,x,y);
graph.FillRectangle(Brushes.White, ImageSize);
}
return bmp;
}
You are assigning a new image to resultImage, thereby overwriting your previous attempt at creating a white image (which should succeed, by the way).
So just remove the line
resultImage = new Bitmap(image1.Width, image1.Height, grp);
Another approach,
Create a unit bitmap
var b = new Bitmap(1, 1);
b.SetPixel(0, 0, Color.White);
And scale it
var result = new Bitmap(b, 1024, 1024);
Graphics.Clear(Color)
Bitmap bmp = new Bitmap(1024, 1024);
using (Graphics g = Graphics.FromImage(bmp)){g.Clear(Color.White);}
Depending on your needs, a BitmapSource might suit. You can quickly fill a byte array with the 0xff (i.e. white) using Enumerable.Repeat().
int w = 1024;
int h = 1024;
byte[] pix = Enumerable.Repeat((byte)0xff, w * h * 4).ToArray();
SomeImage.Source = BitmapSource.Create(w, h, 96, 96, PixelFormats.Pbgra32, null, pix, w * 4);
as stated in subject, i have an image:
private Image testing;
testing = new Bitmap(#"sampleimg.jpg");
I would like to split it into 3 x 3 matrix meaning 9 images in total and save it.Any tips or tricks to do this simple? I'm using visual studios 2008 and working on smart devices. Tried some ways but i can't get it. This is what i tried:
int x = 0;
int y = 0;
int width = 3;
int height = 3;
int count = testing.Width / width;
Bitmap bmp = new Bitmap(width, height);
Graphics g = Graphics.FromImage(bmp);
for (int i = 0; i < count; i++)
{
g.Clear(Color.Transparent);
g.DrawImage(testing, new Rectangle(0, 0, width, height), new Rectangle(x, y, width, height), GraphicsUnit.Pixel);
bmp.Save(Path.ChangeExtension(#"C\AndrewPictures\", String.Format(".{0}.bmp",i)));
x += width;
}
Depending on the .NET version, you could do one of the following to crop:
.NET 2.0
private static Image cropImage(Image img, Rectangle cropArea)
{
Bitmap bmpImage = new Bitmap(img);
Bitmap bmpCrop = bmpImage.Clone(cropArea,
bmpImage.PixelFormat);
return (Image)(bmpCrop);
}
Or .NET 3.5+
// Create an Image element.
Image croppedImage = new Image();
croppedImage.Width = 200;
croppedImage.Margin = new Thickness(5);
// Create a CroppedBitmap based off of a xaml defined resource.
CroppedBitmap cb = new CroppedBitmap(
(BitmapSource)this.Resources["masterImage"],
new Int32Rect(30, 20, 105, 50)); //select region rect
croppedImage.Source = cb; //set image source to cropped
As you can see, it's a bit more simple than what you're doing. The first example clones the current image and takes a subset of it; the second example uses CroppedBitmap, which supports taking a section of the image right from the constructor.
The splitting part is simple maths, just splitting the image into 9 sets of coordinates and passing them into the constructor.