We have recently started using ImageResizer.Net over GDI+ for dynamically resizing images on our ASP.NET MVC 4 application.
Is there a way, using only ImageResizer, to determine the actual resolution(DPI,PPI, whatever you want to call it), of the image (which is read in as a byte array). We currently have a workflow like this, to resize the image to a specified lower resolution when needed:
//pseudo-code
var image = (Bitmap)Bitmap.FromStream(contentStream)
var resX = image.HorizontalResolution;
var resY = image.VerticalResolution;
//calculate scale factor
//determine newHeight and newWidth from scale
var settings = new ResizeSettings("width={newWidth}&height={newHeight}")
var newImage = ImageBuilder.Current.Build(image, someNewImage, settings);
This works fine, but its mixing GDI+ and ImageResizer, and has alot of stream opening and closing of the same data (the actual code is a bit more verbose, with many using
statements).
Is there a way to determine the Horizontal and Vertical Resolution using just ImageResizer? I couldn't immediately find anything in the documentation.
For the moment, we have used the managed api, but will eventually use the MVC routing.
This is a rather atypical scenario - normally incoming DPI values are worthless.
However, since it appears you control those values, and need them to perform sizing calculations, I suggest a plugin. They're easy, and offer ideal performance since you're not duplicating effort.
public class CustomSizing:BuilderExtension, IPlugin {
public CustomSizing() { }
public IPlugin Install(Configuration.Config c) {
c.Plugins.add_plugin(this);
return this;
}
public bool Uninstall(Configuration.Config c) {
c.Plugins.remove_plugin(this);
return true;
}
//Executes right after the bitmap has been loaded and rotated/paged
protected override RequestedAction PostPrepareSourceBitmap(ImageState s) {
//I suggest only activating this logic if you get a particular querystring command.
if (!"true".Equals(s.settings["customsizing"],
StringComparison.OrdinalIgnoreCase)) return RequestedAction.None;
//s.sourceBitmap.HorizontalResolution
//s.sourceBitmap.VerticalResolution
//Set output pixel dimensions and fit mode
//s.settings.Width = X;
//s.settings.Height = Y;
//s.settings.Mode = FitMode.Max;
//Set output res.
//s.settings["dpi"] = "96";
return RequestedAction.None;
}
}
Installation can be done through code or via Web.Config.
new CustomSizing().Install(Config.Current);
or in the resizer's configuration section:
<plugins>
<add name="MyNamespace.CustomSizing" />
</plugins>
Is this what your looking for ?
http://nathanaeljones.github.com/resizer-docs/docu/ImageResizer.Resizing/ImageState.htm#originalSize
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