Develop Reference

Resized WriteableBitmap corruption

I have a method to resize the image like below.
public static WriteableBitmap ResizedBitmap(BitmapImage imgPhoto, int Width, int Height)
{
int sourceWidth = (int)imgPhoto.PixelWidth;
int sourceHeight = (int)imgPhoto.PixelHeight;
int destX = 0;
int destY = 0;
float nPercent = 0;
float nPercentW = 0;
float nPercentH = 0;
nPercentW = ((float)Width / (float)sourceWidth);
nPercentH = ((float)Height / (float)sourceHeight);
if (nPercentH < nPercentW)
{
nPercent = nPercentH;
destX = System.Convert.ToInt16((Width -
(sourceWidth * nPercent)) / 2);
}
else
{
nPercent = nPercentW;
destY = System.Convert.ToInt16((Height -
(sourceHeight * nPercent)) / 2);
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
WriteableBitmap bmPhoto = new WriteableBitmap(imgPhoto);
WriteableBitmap resizedBitmap = bmPhoto.Resize(destWidth, destHeight, WriteableBitmapExtensions.Interpolation.NearestNeighbor);
return resizedBitmap;
}
I am using WritableBitmapEx library and after resizing my image I convert it to a byte array using code below in client side:
using (FileStream stream = openFileDialog.File.OpenRead())
{
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.SetSource(stream);
WriteableBitmap resizedWriteableBitmap = ImageHelper.ResizedBitmap(bitmapImage, 150, 200);
member_Image.Source = resizedWriteableBitmap;
memberImageByteArray = resizedWriteableBitmap.ToByteArray();
fileExtension = fileInfo.Extension;
}
Then I am writing bytes to file in server side using BinaryWriter. However I cannot see the image. When I open the file, it says file is currupted. If I send picture array without resizing there is no problem. Is there a bug with WriteableBitmapEx library or something wrong with my code?

After image resize transparency is removed - gdi+

I am reading an image from file that contains transparency area in the center (frame image type).
Image myFrame = Image.FromFile("d:\mypngfile.png");
After i call image resize custome function:
myFrame = resizeImage(myFrame, new Size(otherbmp.Width, otherbmp.Height));
The problem is that after reszing the image it seems transparency is removed.
resize function:
public Image resizeImage(Image imgToResize, Size size)
{
int sourceWidth = imgToResize.Width;
int sourceHeight = imgToResize.Height;
float nPercent = 0;
float nPercentW = 0;
float nPercentH = 0;
nPercentW = ((float)size.Width / (float)sourceWidth);
nPercentH = ((float)size.Height / (float)sourceHeight);
if (nPercentH < nPercentW)
nPercent = nPercentH;
else
nPercent = nPercentW;
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap b = new Bitmap(destWidth, destHeight,PixelFormat.Format32bppArgb);
b.MakeTransparent();
Graphics g = Graphics.FromImage((Image)b);
g.CompositingQuality = CompositingQuality.HighQuality;
g.CompositingMode = CompositingMode.SourceOver;
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.SmoothingMode = SmoothingMode.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
g.Dispose();
return (Image)b;
}
After i am checking the alpha pixels which doesn't work after resize (it does work before resizing and returns a value). It always return 0!
public int GetBorderWidth(Bitmap bmp)
{
var hy = bmp.Height/ 2;
while (bmp.GetPixel(0, hy).A == 255 && sz.Width < hx)
sz.Width++;
return sz.width;
}
I can't seem to solve this issue no matter what i try...

I found the issue, it was related that after resizing the image it seems that the border has some transparent pixels ..(like Alpha 150) so the border was not ALPHA 255..
What i did i changed the function GetBorderWidth code with
while (bmp.GetPixel(sz.Width, hy).A > 10 && sz.Width < hx)
sz.Width++;
and it seems it fixed the issue.
thank you all for giving me some idea of what to check.

GDI Transparent Background C#

I am using windows GDI Library to resize the image using the following code. I am trying to generate the transparent images. This function is called from from and function that generates images. If I save the image without resizing I am getting transparency
static Image FixedSize(Image imgPhoto, int Width, int Height)
{
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
float nPercent = 0;
float nPercentW = 0;
float nPercentH = 0;
nPercentW = ((float)Width/(float)sourceWidth);
nPercentH = ((float)Height/(float)sourceHeight);
if(nPercentH < nPercentW)
{
nPercent = nPercentH;
destX = System.Convert.ToInt16((Width -
(sourceWidth * nPercent))/2);
}
else
{
nPercent = nPercentW;
destY = System.Convert.ToInt16((Height -
(sourceHeight * nPercent))/2);
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(Width, Height,
PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution,
imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.Clear(Color.Transparent);
grPhoto.InterpolationMode =
InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX,destY,destWidth,destHeight),
new Rectangle(sourceX,sourceY,sourceWidth,sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
fileName= txtImgName.text();
bitmap.Save(Server.MapPath("~/images32/") + fileName, ImageFormat.Png);
}
I am getting the image resized but the problem is that it is having black background.
Please help me in generating Transparent Image
Thanks in Advance

I guess that is because you use a bitmap with RGB colors (Format24bppRgb) as source.
Use one that contains an alpha channel, such as Format32bppArgb.

some issues with downsized images and their increased file sizes in c#

I have a class which helps me out to re-size my images to a specified image size but the problem is with the file sizes of the output images—actually it's kinda funny but here is the thing:
the original image is : 800x600 24bit 96dpi file-size : 82kb
the re-size image is : 466x340 24bit 96dpi file-size : 366kb
what should I do? is there any 3rd party component or open source project according to this issue?
here is my mentioned class :
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
public class imageClass
{
public enum Dimensions
{
Width,
Height
}
public enum AnchorPosition
{
Top,
Center,
Bottom,
Left,
Right
}
public static Image ScaleByPercent(Image imgPhoto, int Percent)
{
float nPercent = ((float)Percent / 100);
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(destWidth, destHeight, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, destWidth, destHeight),
new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
return bmPhoto;
}
public static Image ConstrainProportions(Image imgPhoto, int Size, Dimensions Dimension)
{
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
float nPercent = 0;
switch (Dimension)
{
case Dimensions.Width:
nPercent = ((float)Size / (float)sourceWidth);
break;
default:
nPercent = ((float)Size / (float)sourceHeight);
break;
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(destWidth, destHeight, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, destWidth, destHeight),
new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
return bmPhoto;
}
public static Image FixedSize(Image imgPhoto, int Width, int Height)
{
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
float nPercent = 0;
float nPercentW = 0;
float nPercentH = 0;
nPercentW = ((float)Width / (float)sourceWidth);
nPercentH = ((float)Height / (float)sourceHeight);
//if we have to pad the height pad both the top and the bottom
//with the difference between the scaled height and the desired height
if (nPercentH < nPercentW)
{
nPercent = nPercentH;
destX = (int)((Width - (sourceWidth * nPercent)) / 2);
}
else
{
nPercent = nPercentW;
destY = (int)((Height - (sourceHeight * nPercent)) / 2);
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.Clear(Color.Red);
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, destWidth, destHeight),
new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
return bmPhoto;
}
public static Image Crop(Image imgPhoto, int Width, int Height, AnchorPosition Anchor)
{
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
int sourceX = 0;
int sourceY = 0;
int destX = 0;
int destY = 0;
float nPercent = 0;
float nPercentW = 0;
float nPercentH = 0;
nPercentW = ((float)Width / (float)sourceWidth);
nPercentH = ((float)Height / (float)sourceHeight);
if (nPercentH < nPercentW)
{
nPercent = nPercentW;
switch (Anchor)
{
case AnchorPosition.Top:
destY = 0;
break;
case AnchorPosition.Bottom:
destY = (int)(Height - (sourceHeight * nPercent));
break;
default:
destY = (int)((Height - (sourceHeight * nPercent)) / 2);
break;
}
}
else
{
nPercent = nPercentH;
switch (Anchor)
{
case AnchorPosition.Left:
destX = 0;
break;
case AnchorPosition.Right:
destX = (int)(Width - (sourceWidth * nPercent));
break;
default:
destX = (int)((Width - (sourceWidth * nPercent)) / 2);
break;
}
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, destWidth, destHeight),
new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
return bmPhoto;
}
}
regards.
the file format I'm using is : JPEG

This is a normal side-effect of resampling the image with the InterpolationMode set to a high quality value, like Bicubic. This subtly alters the pixel values of just about every pixel, especially since jpeg decompression produces subtle noise in the image. Barely visible to the human eye, quite visible to the resampling filter. Giving the jpeg encoder a much harder time compressing the image. Only starting out with a non-compressed image format, like PNG, can improve the outcome.

If you are not explicitly defining an image format, it will default to BMP or PNG format. If you do explicitly specify ImageFomat.Jpeg, it will use quality=100, instead of quality=90 (the best setting, with no discernable differences). Check out the 28 image resizing pitfalls if you aren't going to use the recommended library for this situation
The ImageResizer library
You mentioned a library, and yes, it exists. The ImageResizer library avoids all of the GDI bugs, defaults to quality=90, and doesn't leak memory or GDI handles, even when images are corrupted. It also supports autocropping, manual cropping, resizing, rotating, and a ton of other features. It's time tested, traffic tested, and unit tested.
It has a 1-line API that is very simple to use.
Go check it out!

Digital Persona Finger Print captured image as WSQ

I'm using Digital Persona Finger Print device and need to capture the image as WSQ format instead of Bmp format
Using C# DigitalPersona One Touch for Windows SDK
Sample Code
private DPFP.Capture.SampleConversion SampleConversion;
private Bitmap Image;
public async void OnComplete(object Capture, string ReaderSerialNumber, DPFP.Sample Sample)
{
var imgName = string.Format("fingerprint{0}.bmp", DateTime.Now.Ticks);
SampleConversion.ConvertToPicture(Sample, ref Image);
Image.Save(imgName, System.Drawing.Imaging.ImageFormat.Bmp);
}
I found library in C# that convert bmp to wsq wsqEncodeDecode but the result of wsq are not correct, Any solution that return the captured image in wsq format directly from the sdk?

To Achieve exactly what i need i do the following:
I used 2 libraries
1 - AForge.Imaging , AForge.Imaging.Formats and Delta.Wsq DLL's
private Bitmap Image;
public async void OnComplete(object Capture, string ReaderSerialNumber, DPFP.Sample Sample)
{
SampleConversion.ConvertToPicture(Sample, ref Image);
Image.RotateFlip(RotateFlipType.Rotate180FlipNone);
Image = resizeImage(364, 400, Image);
var img8bppx = Grayscale.CommonAlgorithms.BT709.Apply(Image);
var rawImageData = Conversions.GdiImageToImageInfo(img8bppx);
WsqEncoder encoder = new WsqEncoder();
var result = encoder.Encode(rawImageData);
}
And is method to do resize
public Bitmap resizeImage(int newWidth, int newHeight, Image imgPhoto)
{
int sourceWidth = imgPhoto.Width;
int sourceHeight = imgPhoto.Height;
//Consider vertical pics
if (sourceWidth < sourceHeight)
{
int buff = newWidth;
newWidth = newHeight;
newHeight = buff;
}
int sourceX = 0, sourceY = 0, destX = 0, destY = 0;
float nPercent = 0, nPercentW = 0, nPercentH = 0;
nPercentW = ((float)newWidth / (float)sourceWidth);
nPercentH = ((float)newHeight / (float)sourceHeight);
if (nPercentH < nPercentW)
{
nPercent = nPercentH;
destX = System.Convert.ToInt16((newWidth -
(sourceWidth * nPercent)) / 2);
}
else
{
nPercent = nPercentW;
destY = System.Convert.ToInt16((newHeight -
(sourceHeight * nPercent)) / 2);
}
int destWidth = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);
Bitmap bmPhoto = new Bitmap(newWidth, newHeight,
PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution,
imgPhoto.VerticalResolution);
Graphics grPhoto = Graphics.FromImage(bmPhoto);
grPhoto.Clear(Color.Black);
grPhoto.InterpolationMode =
System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
grPhoto.DrawImage(imgPhoto,
new Rectangle(destX, destY, destWidth, destHeight),
new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight),
GraphicsUnit.Pixel);
grPhoto.Dispose();
imgPhoto.Dispose();
return bmPhoto;
}