I'm making an app that can save to PDF image of my controls (datagrids etc).
The controls are big - width and height, with scrolls.
And my app can paginate view of this controls for saving to PDF or can save without paginating.
If i add my control to Fixed Page, it works fine, the quality is superior, but it takes a long time to save such file and it "eats" lot of space. But if i firstly make a bitmap image of this control, then save it to PDF, the quality is getting poor for some page sizes, though it makes PDF file much more lightweight.
The process goes that way:
Paginating (or not - depends on settings) with visualbrush - > Make a bitmap (bmp) -> Save to PDF.
If my page size is about A4, A3 or A2 - the quality is OK. But if i set bigger size - A1 or A0, the quality is getting so poor, that text can't be read.
If i make some other way: Paginating (or not - depends on settings) with visualbrush - > Save to PDF - without part of making bitmap image of my control, everything is good, A1 and A0 ...and even bigger page sizes looks good, but PDF file becomes much more bigger and it takes more time to save.
Is this because of some bitmap features for big sizes or something goes wrong? I mean, why the quality for A4, A3 and A2 sizes is OK, and for bigger sizes is poor?
I've also tried to change dpi or render sizes and some other attributes, but i couldn't get some good result.
Here is my code for making image of control:
private Image GetPageImage(FrameworkElement element, Size pageSize, double dpiX = 0, double dpiY = 0)
{
//Get current dpi
if (dpiX == 0 || dpiY == 0) { dpiX = PrintProperties.GetDpi()[0];dpiY = PrintProperties.GetDpi()[1]; }
//Check element measure
if (!element.IsMeasureValid)
{
Size size = new Size(element.Width, element.Height);
element.Measure(size);
element.Arrange(new Rect(size));
}
element.ApplyTemplate();
element.UpdateLayout();
Image pageImage = new Image();
double renderHeight = element.Height;
double renderWidth = element.Width;
if (element.DesiredSize.Width > (pageSize.Width-2*_margin) || element.DesiredSize.Height> (pageSize.Height-2*_margin))
{
if(element.Height>element.Width)
{
renderHeight = pageSize.Height - _margin * 2;
renderWidth = element.Width*(renderHeight / element.Height);
}
else
{
renderWidth = pageSize.Width - _margin * 2;
renderHeight = element.Height * (renderWidth / element.Width);
}
}
element.RenderSize = new Size(renderWidth, renderHeight);
var rect = new Rect(element.RenderSize);
var visual = new DrawingVisual();
using (var dc = visual.RenderOpen())
{
dc.DrawRectangle(new VisualBrush(element), null, rect);
}
var bitmap = new RenderTargetBitmap((int)element.Width, (int)element.Height, dpiX, dpiY, PixelFormats.Default);
bitmap.Render(visual);
pageImage.Source = bitmap;
return pageImage;
}
Related
Yes yes... I've seen other posts related to this issue, and yes... I've googled about it.
But so far, I was not able to get to the result I need.
I'm loading a large image taken in 300 dpi, and I need to resize it.
I know... I know... dpi is relative and doesn't really matter... what matters are the dimensions in pixels:
DPI is essentially the number of pixels that correspond to an inch when the image is printed not when it is viewed on a screen. Therefore by increasing the DPI of the image, you do not increase the size of the image on the screen. You only increase the quality of print.
Even though the DPI information stored in the EXIF of an image is somewhat useless, it is causing me problems.
The image I'm resizing is losing the original exif information, including the horizontal and vertical resolution (dpi), and thus it is saving with a default of 96 dpi. Possible reason to this is that only JPEG and another format can hold metadata information.
The end image result is should look like this: 275x375 at 300dpi
Instead is looking like this: 275x375 at 96dpi
You can argue that they are they same, and I agree, but we have a corel draw script that used to load these images, and since this dpi information is different, it places it in different sizes on the document.
Here's what I'm using for resizing:
public System.Drawing.Bitmap ResizeImage(System.Drawing.Image image, int width, int height)
{
Bitmap result = new Bitmap(width, height);
// set the resolutions the same to avoid cropping due to resolution differences
result.SetResolution(image.HorizontalResolution, image.VerticalResolution);
//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//set the resize quality modes to high quality
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//draw the image into the target bitmap
graphics.DrawImage(image, 0, 0, result.Width, result.Height);
}
//return the resulting bitmap
return result;
}
That does the work very well, but loses the EXIF information.
Setting the SetResolution to SetResolution(300, 300) does not work!
I looked at reading and changing the EXIF information of an image, and I've tried:
public void setImageDpi(string Filename, string NewRes)
{
Image Pic;
PropertyItem[] PropertyItems;
byte[] bDescription = new Byte[NewRes.Length];
int i;
string FilenameTemp;
System.Drawing.Imaging.Encoder Enc = System.Drawing.Imaging.Encoder.Transformation;
EncoderParameters EncParms = new EncoderParameters(1);
EncoderParameter EncParm;
ImageCodecInfo CodecInfo = GetEncoderInfo("image/jpeg");
// copy description into byte array
for (i = 0; i < NewRes.Length; i++) bDescription[i] = (byte)NewRes[i];
// load the image to change
Pic = Image.FromFile(Filename);
foreach (PropertyItem item in Pic.PropertyItems)
{
if (item.Id == 282 || item.Id == 283)
{
PropertyItem myProperty = item;
myProperty.Value = bDescription;
myProperty.Type = 2;
myProperty.Len = NewRes.Length;
Pic.SetPropertyItem(item);
Console.WriteLine(item.Type);
}
}
// we cannot store in the same image, so use a temporary image instead
FilenameTemp = Filename + ".temp";
// for lossless rewriting must rotate the image by 90 degrees!
EncParm = new EncoderParameter(Enc, (long)EncoderValue.TransformRotate90);
EncParms.Param[0] = EncParm;
// now write the rotated image with new description
Pic.Save(FilenameTemp, CodecInfo, EncParms);
// for computers with low memory and large pictures: release memory now
Pic.Dispose();
Pic = null;
GC.Collect();
// delete the original file, will be replaced later
System.IO.File.Delete(Filename);
// now must rotate back the written picture
Pic = Image.FromFile(FilenameTemp);
EncParm = new EncoderParameter(Enc, (long)EncoderValue.TransformRotate270);
EncParms.Param[0] = EncParm;
Pic.Save(Filename, CodecInfo, EncParms);
// release memory now
Pic.Dispose();
Pic = null;
GC.Collect();
// delete the temporary picture
System.IO.File.Delete(FilenameTemp);
}
That didn't work either.
I tried looking and changing the EXIF information for DPI (282 and 283) later in the process as such:
Encoding _Encoding = Encoding.UTF8;
Image theImage = Image.FromFile("somepath");
PropertyItem propItem282 = theImage.GetPropertyItem(282);
propItem282.Value = _Encoding.GetBytes("300" + '\0');
theImage.SetPropertyItem(propItem282);
PropertyItem propItem283 = theImage.GetPropertyItem(283);
propItem283.Value = _Encoding.GetBytes("300" + '\0');
theImage.SetPropertyItem(propItem283);
theImage.Save("somepath");
But the program crashes saying that Property Cannot be Found.
If the property doesn't exist, apparently I can't add it:
A PropertyItem is not intended to be used as a stand-alone object. A PropertyItem object is intended to be used by classes that are derived from Image. A PropertyItem object is used to retrieve and to change the metadata of existing image files, not to create the metadata. Therefore, the PropertyItem class does not have a defined Public constructor, and you cannot create an instance of a PropertyItem object.
I'm stuck... all I need is a resized image with a dpi set to 300, it shouldn't be so hard.
Any help much appreciated. Thanks
The following code worked for me:
const string InputFileName = "test_input.jpg";
const string OutputFileName = "test_output.jpg";
var newSize = new Size(640, 480);
using (var bmpInput = Image.FromFile(InputFileName))
{
using (var bmpOutput = new Bitmap(bmpInput, newSize))
{
foreach (var id in bmpInput.PropertyIdList)
bmpOutput.SetPropertyItem(bmpInput.GetPropertyItem(id));
bmpOutput.SetResolution(300.0f, 300.0f);
bmpOutput.Save(OutputFileName, ImageFormat.Jpeg);
}
}
When I inspect the output file I can see EXIF data and the DPI has been changed to 300.
In my project, I want to generate thumbnail from images that uploaded by user and show it in a gallery ( showing in a div box with size : 180 x 250). Below is code that i'm using to do it.
Size thumbnailSize = GetThumbnailSize(img);
System.Drawing.Image thumbnail = img.GetThumbnailImage(thumbnailSize.Width, thumbnailSize.Height, null, IntPtr.Zero);
.....
private Size GetThumbnailSize(System.Drawing.Image original)
{
const int maxPixels = 300;
int originalWidth = original.Width;
int originalHeight = original.Height;
double factor;
if (originalWidth > originalHeight)
{
factor = (double)maxPixels / originalWidth;
}
else
{
factor = (double)maxPixels / originalHeight;
}
return new Size((int)(originalWidth * factor), (int)(originalHeight * factor));
}
My problem is, the generated thumbnail is only suitable for image that large size, when user upload image that are smaller(eg:30 x 30), the thumbnail that generated will be zoom in and not clear shown like below. So what to do in order to generate thumbnail that are in ratio and can show properly in my gallery div box no matter the image is large or small?
I would recommend to check if the Image is smaller then the size you want to have. If it is not treat it like you allready do. If it is smaller copy the image data into the center of a blank image that has the size you want to have and display this as thumbnail.
Yes yes... I've seen other posts related to this issue, and yes... I've googled about it.
But so far, I was not able to get to the result I need.
I'm loading a large image taken in 300 dpi, and I need to resize it.
I know... I know... dpi is relative and doesn't really matter... what matters are the dimensions in pixels:
DPI is essentially the number of pixels that correspond to an inch when the image is printed not when it is viewed on a screen. Therefore by increasing the DPI of the image, you do not increase the size of the image on the screen. You only increase the quality of print.
Even though the DPI information stored in the EXIF of an image is somewhat useless, it is causing me problems.
The image I'm resizing is losing the original exif information, including the horizontal and vertical resolution (dpi), and thus it is saving with a default of 96 dpi. Possible reason to this is that only JPEG and another format can hold metadata information.
The end image result is should look like this: 275x375 at 300dpi
Instead is looking like this: 275x375 at 96dpi
You can argue that they are they same, and I agree, but we have a corel draw script that used to load these images, and since this dpi information is different, it places it in different sizes on the document.
Here's what I'm using for resizing:
public System.Drawing.Bitmap ResizeImage(System.Drawing.Image image, int width, int height)
{
Bitmap result = new Bitmap(width, height);
// set the resolutions the same to avoid cropping due to resolution differences
result.SetResolution(image.HorizontalResolution, image.VerticalResolution);
//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//set the resize quality modes to high quality
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//draw the image into the target bitmap
graphics.DrawImage(image, 0, 0, result.Width, result.Height);
}
//return the resulting bitmap
return result;
}
That does the work very well, but loses the EXIF information.
Setting the SetResolution to SetResolution(300, 300) does not work!
I looked at reading and changing the EXIF information of an image, and I've tried:
public void setImageDpi(string Filename, string NewRes)
{
Image Pic;
PropertyItem[] PropertyItems;
byte[] bDescription = new Byte[NewRes.Length];
int i;
string FilenameTemp;
System.Drawing.Imaging.Encoder Enc = System.Drawing.Imaging.Encoder.Transformation;
EncoderParameters EncParms = new EncoderParameters(1);
EncoderParameter EncParm;
ImageCodecInfo CodecInfo = GetEncoderInfo("image/jpeg");
// copy description into byte array
for (i = 0; i < NewRes.Length; i++) bDescription[i] = (byte)NewRes[i];
// load the image to change
Pic = Image.FromFile(Filename);
foreach (PropertyItem item in Pic.PropertyItems)
{
if (item.Id == 282 || item.Id == 283)
{
PropertyItem myProperty = item;
myProperty.Value = bDescription;
myProperty.Type = 2;
myProperty.Len = NewRes.Length;
Pic.SetPropertyItem(item);
Console.WriteLine(item.Type);
}
}
// we cannot store in the same image, so use a temporary image instead
FilenameTemp = Filename + ".temp";
// for lossless rewriting must rotate the image by 90 degrees!
EncParm = new EncoderParameter(Enc, (long)EncoderValue.TransformRotate90);
EncParms.Param[0] = EncParm;
// now write the rotated image with new description
Pic.Save(FilenameTemp, CodecInfo, EncParms);
// for computers with low memory and large pictures: release memory now
Pic.Dispose();
Pic = null;
GC.Collect();
// delete the original file, will be replaced later
System.IO.File.Delete(Filename);
// now must rotate back the written picture
Pic = Image.FromFile(FilenameTemp);
EncParm = new EncoderParameter(Enc, (long)EncoderValue.TransformRotate270);
EncParms.Param[0] = EncParm;
Pic.Save(Filename, CodecInfo, EncParms);
// release memory now
Pic.Dispose();
Pic = null;
GC.Collect();
// delete the temporary picture
System.IO.File.Delete(FilenameTemp);
}
That didn't work either.
I tried looking and changing the EXIF information for DPI (282 and 283) later in the process as such:
Encoding _Encoding = Encoding.UTF8;
Image theImage = Image.FromFile("somepath");
PropertyItem propItem282 = theImage.GetPropertyItem(282);
propItem282.Value = _Encoding.GetBytes("300" + '\0');
theImage.SetPropertyItem(propItem282);
PropertyItem propItem283 = theImage.GetPropertyItem(283);
propItem283.Value = _Encoding.GetBytes("300" + '\0');
theImage.SetPropertyItem(propItem283);
theImage.Save("somepath");
But the program crashes saying that Property Cannot be Found.
If the property doesn't exist, apparently I can't add it:
A PropertyItem is not intended to be used as a stand-alone object. A PropertyItem object is intended to be used by classes that are derived from Image. A PropertyItem object is used to retrieve and to change the metadata of existing image files, not to create the metadata. Therefore, the PropertyItem class does not have a defined Public constructor, and you cannot create an instance of a PropertyItem object.
I'm stuck... all I need is a resized image with a dpi set to 300, it shouldn't be so hard.
Any help much appreciated. Thanks
The following code worked for me:
const string InputFileName = "test_input.jpg";
const string OutputFileName = "test_output.jpg";
var newSize = new Size(640, 480);
using (var bmpInput = Image.FromFile(InputFileName))
{
using (var bmpOutput = new Bitmap(bmpInput, newSize))
{
foreach (var id in bmpInput.PropertyIdList)
bmpOutput.SetPropertyItem(bmpInput.GetPropertyItem(id));
bmpOutput.SetResolution(300.0f, 300.0f);
bmpOutput.Save(OutputFileName, ImageFormat.Jpeg);
}
}
When I inspect the output file I can see EXIF data and the DPI has been changed to 300.
I am trying to save an image from string.
so I want to know how I can set image height and width in inches at the time of saving the image.
my code follows for image saving :
private void Base64ToImage(string base64String)
{
Image fullSizeImg = null;
byte[] imageBytes = Convert.FromBase64String(base64String);
MemoryStream ms = new MemoryStream(imageBytes);
fullSizeImg = Image.FromStream(ms, true);
System.Drawing.Image.GetThumbnailImageAbort dummyCallBack = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);
System.Drawing.Image thumbNailImg = fullSizeImg.GetThumbnailImage(700, 800, dummyCallBack, IntPtr.Zero);
thumbNailImg.Save(ImagePath, System.Drawing.Imaging.ImageFormat.Png);
fullSizeImg.Dispose();
thumbNailImg.Dispose();
}
That doesn't work. We save in pixels because an inch/cm/mile does not convert to on-screen real estate. The reason for this is that we all use different DPI settings, albeit 92 DPI seems to be one of the more common settings nowadays.
There are also varying DPI settings for printers...
To calculate the pixels from inches, you could try:
pixels = inches * someDpiSetting
but bear in mind this will not result in inches on every screen, every printout, etc.
EDIT: If you take a look at WPF you'll find that it has fantastic support for DPI, and will translate a form to the same (give or take) size regardless of DPI. Maybe that helps?
Bitmaps don't have a size in inches, their size is measured in pixels. That said most modern bitmat formats have a piece of metadata called DPI (dots per inch) that is used to translate a size in pixels to a size in inches via the simple formula:
inches = pixels / dpi
For the Image class you set metadata using the SetPropertyItem Method where the pieces of metadata we are interested in are:
PropertyTagResolutionUnit - set this to "2" for inches
PropertyTagXResolution - Essentially the X DPI as long as PropertyTagResolutionUnit is in inches.
PropertyTagYResolution - The Y DPI as long as PropertyTagResolutionUnit is in inches
See Property Item Descriptions for details.
(Actually, I realised half way through writing this that the setting of property metadata using SetPropertyItem looks really complicated - you might just be better off using Bitmat instead, which has resolution properties making the whole thing a lot easier)
As a contrast to those imperial measures and formula-only's:
// inches = pixels / dpi
// pixel = inches * dpi
// 1 centimeter = 0.393700787 inch
// pixel = cm * 0.393700787 * dpi
single sngWidth = 2.25; //cm
single sngHeight = 1.0; //cm
sngWidth *= 0.393700787 * bmpImage.HorizontalResolution; // x-Axis pixel
sngHeight *= 0.393700787 * bmpImage.VerticalResolution; // y-Axis pixel
Like so:
public static int Cm2Pixel(double WidthInCm)
{
double HeightInCm = WidthInCm;
return Cm2Pixel(WidthInCm, HeightInCm).Width;
} // End Function Cm2Pixel
public static System.Drawing.Size Cm2Pixel(double WidthInCm, double HeightInCm)
{
float sngWidth = (float)WidthInCm; //cm
float sngHeight = (float)HeightInCm; //cm
using (System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(1, 1))
{
sngWidth *= 0.393700787f * bmp.HorizontalResolution; // x-Axis pixel
sngHeight *= 0.393700787f * bmp.VerticalResolution; // y-Axis pixel
}
return new System.Drawing.Size((int)sngWidth, (int)sngHeight);
} // End Function Cm2Pixel
If you are using a Bitmap then it has the method SetResolution (http://msdn.microsoft.com/en-us/library/system.drawing.bitmap.setresolution.aspx) that allows you to set the x and y dpi which can be easily derived from your knowledge of the height and width of the image in pixels and inches that you already have.
I'm hoping here that using a Bitmap instead of an Image shouldn't be a problem. Its a subclass so I would imagine it is likely you can.
MemoryStream ms = new MemoryStream();
new FileStream(Afiladdress, FileMode.Open).CopyTo(ms);
Bitmap myimage = new Bitmap(ms);
float Width = myimage.Width / myimage.HorizontalResolution;//in INCHES
float Height= myimage.Height/ myimage.VerticalResolution;//in INCHES
I am using the following code in my website, for thumbnail creation:
string furl = "~/images/thumbs/" + matchString;
lBlogThumb.ImageUrl = GetThumbnailView(furl, 200, 200);
private string GetThumbnailView(string originalImagePath, int height, int width)
{
//Consider Image is stored at path like "ProductImage\\Product1.jpg"
//Now we have created one another folder ProductThumbnail to store thumbnail image of product.
//So let name of image be same, just change the FolderName while storing image.
string thumbnailImagePath = originalImagePath.Replace("thumbs", "thumbs2");
//If thumbnail Image is not available, generate it.
if (!System.IO.File.Exists(Server.MapPath(thumbnailImagePath)))
{
System.Drawing.Image imThumbnailImage;
System.Drawing.Image OriginalImage = System.Drawing.Image.FromFile(Server.MapPath(originalImagePath));
imThumbnailImage = OriginalImage.GetThumbnailImage(width, height,
new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero);
imThumbnailImage.Save(Server.MapPath(thumbnailImagePath), System.Drawing.Imaging.ImageFormat.Jpeg);
imThumbnailImage.Dispose();
OriginalImage.Dispose();
}
return thumbnailImagePath;
}
public bool ThumbnailCallback() { return false; }
I would like to change this code, and be able to create a thumbnail defining width ONLY. What I have in mind is actually something like cropping/resizing image, using a static width, maintaining it's ratio. Is that possible;
You mention resizing and cropping. If you want the thumbnail heights to vary with a fixed width, the answers provided already will work for you.
The mention of cropping makes me think that you may want a fixed thumbnail size, with the width filled and any overflowing vertical portion cropped off. If that is the case, you'll need to do a bit more work. I needed something similar recently, and this is what I came up with.
This will create a thumbnail of the original that is sized and cropped in such a way that the source image completely fills the target thumbnail, cropping any overflow. There will be no borders within the thumbnail, even if the original and thumbnail aspect ratios are different.
public System.Drawing.Image CreateThumbnail(System.Drawing.Image image, Size thumbnailSize)
{
float scalingRatio = CalculateScalingRatio(image.Size, thumbnailSize);
int scaledWidth = (int)Math.Round((float)image.Size.Width * scalingRatio);
int scaledHeight = (int)Math.Round((float)image.Size.Height * scalingRatio);
int scaledLeft = (thumbnailSize.Width - scaledWidth) / 2;
int scaledTop = (thumbnailSize.Height - scaledHeight) / 2;
// For portrait mode, adjust the vertical top of the crop area so that we get more of the top area
if (scaledWidth < scaledHeight && scaledHeight > thumbnailSize.Height)
{
scaledTop = (thumbnailSize.Height - scaledHeight) / 4;
}
Rectangle cropArea = new Rectangle(scaledLeft, scaledTop, scaledWidth, scaledHeight);
System.Drawing.Image thumbnail = new Bitmap(thumbnailSize.Width, thumbnailSize.Height);
using (Graphics thumbnailGraphics = Graphics.FromImage(thumbnail))
{
thumbnailGraphics.CompositingQuality = CompositingQuality.HighQuality;
thumbnailGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
thumbnailGraphics.SmoothingMode = SmoothingMode.HighQuality;
thumbnailGraphics.DrawImage(image, cropArea);
}
return thumbnail;
}
private float CalculateScalingRatio(Size originalSize, Size targetSize)
{
float originalAspectRatio = (float)originalSize.Width / (float)originalSize.Height;
float targetAspectRatio = (float)targetSize.Width / (float)targetSize.Height;
float scalingRatio = 0;
if (targetAspectRatio >= originalAspectRatio)
{
scalingRatio = (float)targetSize.Width / (float)originalSize.Width;
}
else
{
scalingRatio = (float)targetSize.Height / (float)originalSize.Height;
}
return scalingRatio;
}
To use with your code, you could replace your call to OriginalImage.GetThumbnailImage with this:
imThumbnailImage = CreateThumbnail(OriginalImage, new Size(width, height));
Note that for portrait images, this code will actually shift the thumbnail's viewport slightly higher on the original image. This was done so that portrait shots of people wouldn't result in headless torsos when the thumbnails were created. If you don't want that logic, simply remove the if block following the "portrait mode" comment.
let's have originalWidth=the original image width and thumbWidth. You can simply choose the thumbWidth to your desired value, and calculate the thumbHeigth=originalHeigth*thumbWidth/originalWidth
I got sick of needed to do this and created a lib that does this easily: Link To Documentation & Download
A basic example without rounding with a thumbnail width of 140, below the 'file' is a HttpPostedFile uploaded from an ASP.Net FileUpload control, the HttpPostedFile exposes a stream.
// Save images to disk.
using (System.Drawing.Image image = System.Drawing.Image.FromStream(file.InputStream))
using (System.Drawing.Image thumbnailImage = image.GetThumbnailImage(140, Convert.ToInt32((image.Height / (image.Width / 140))), null, IntPtr.Zero))
{
if (image != null)
{
image.Save(imageFilePath);
thumbnailImage.Save(thumbnailImagePath);
}
else
throw new ArgumentNullException("Image stream is null");
}