How to get Resized/Thumbnail Image : UWP - image

Currently I was working on a UWP application. I captured the ink strokes into an image. Now the same image need to display as a preview. So the original image need to re-size to shorter size or thumbnail need to be generated.
I tried with using the larger image directly as a source to shorter sized image canvas --> not working (visible image quality degrade)
I also used Transcode of image programatically --> same result as above
I test with the same image. Re-sized the same image using paint, and there interestingly the quality of the re-sized image remains good.
Please help me to solve the issue I faced.

I not sure, need to see some code, but could be how you are saving the image? Here an example:
try
{
Windows.Storage.Pickers.FileSavePicker save = new Windows.Storage.Pickers.FileSavePicker();
save.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.Desktop;
save.DefaultFileExtension = “.png”;
save.FileTypeChoices.Add(“PNG”, new string[] { “.png” });
StorageFile filesave = await save.PickSaveFileAsync();
using (IOutputStream fileStream = await filesave.OpenAsync(FileAccessMode.ReadWrite))
{
if (fileStream != null)
{
await m_InkManager.SaveAsync(fileStream);
}
}
}
catch (Exception ex)
{
var dialog = new MessageDialog(ex.Message);
dialog.ShowAsync();
}
I will post a great tutorial of Can Bilgin that explain perfectly all about inking.
Drawing / Inking API in WinRT (C#) – I
Drawing / Inking API in WinRT (C#) – II
Drawing / Inking API in WinRT (C#) – III

Related

.svg Image in MAUI Blazor

i am trying to set an image in to a razor page in MAUI Blazor.
In MAUI (only), there was the aproach, that you have a .svg image in the folder Resources/Images. MAUI then converts the .svg image in a .png image which you can use in the XAML file. like so:
Now i have the same picture in a MAUI Blazor app and i hoped that i can put my picture in the same way expect that i have to use the HTML style like so:
<img src="one_list2.png">
But this doesn't work at all. I tryed with or witout path, path with slashes, backslashes etc. nothing works.
Trying to put a .png image into the wwwroot folder works. But this isn't the goal. I found it very nice to put a svg image which is then converted into a png depending of its size. This way all pictures would be converted exactly in the perfect size you will need lossless.
Thanks
First, Add the image to Resources\Raw and set it to MauiAsset compilation type
Second, Check the project file to avoid setting the image in the other folder.
In razor component HTML:
<img src="#imageSource">
In the code part:
private string? imageSource;
protected override async Task OnInitializedAsync()
{
try
{
using var stream =
await FileSystem.OpenAppPackageFileAsync("testimage.png");
using var reader = new StreamReader(stream);
byte[] result;
using (var streamReader = new MemoryStream())
{
stream.CopyTo(streamReader);
result = streamReader.ToArray();
}
imageSource = Convert.ToBase64String(result);
imageSource = string.Format("data:image/png;base64,{0}", imageSource);
}
catch (Exception ex)
{
//error
}
}
More information you can refer to ASP.NET Core Blazor Hybrid static files.

Crop image from uInt8List Flutter

i an developing an tool for publish image like instagram,
the problem is that i want to cut the image and send to server square, my problem is that t can not cut the image sqaure from the original image, i have a uInt8List from my image.
how can i cut my image?
I wrote an extension on Face from Firebase's Vision Api, it returns you the image bytes data which you can just plug into your Image.memory widget.
Forget to mention you need the image library :
- https://pub.dev/packages/image
extension FaceExtension on Face {
Future<Uint8List> getFaceFromImage(File imageFile) async {
final image = await imageFile.readAsBytes();
final decodedImage = decodeImage(image);
final rectangle = this.boundingBox;
final face = copyCrop(
decodedImage,
rectangle.topLeft.dx.toInt(),
rectangle.topLeft.dy.toInt(),
rectangle.width.toInt(),
rectangle.height.toInt(),
);
return Uint8List.fromList(encodePng(face));
}
}

Save WF 4 workflow as Image

The problem is that I am opening workflow designer dynamically from one shell application and I don't have reference to Canvas. I am able to save the WF4 as image but the image is not getting saved properly and contains left & top margins. I followed many articles to get it working but no success. I referred to following article as well.
Saving a canvas to png C# wpf
I am using the below function. I don't have any reference to canvas.
private BitmapFrame CreateWorkflowImage()
{
const double DPI = 96.0;
Visual areaToSave = ((DesignerView)VisualTreeHelper.GetChild(this.wd.View,
0)).RootDesigner;
Rect bounds = VisualTreeHelper.GetDescendantBounds(areaToSave);
RenderTargetBitmap bitmap = new RenderTargetBitmap((int)bounds.Width,
(int)bounds.Height, DPI, DPI, PixelFormats.Default);
bitmap.Render(areaToSave);
return BitmapFrame.Create(bitmap);
}
Please help on this.
I am able to resolve the issue by referring to again the following link
Saving a canvas to png C# wpf
I got the reference to canvas by using following code
Visual canvas= ((DesignerView)VisualTreeHelper.GetChild(this.WorkflowDesigner1.View, 0)).RootDesigner;
This has resolved the border/margin issue.
Please have a look here: http://blogs.msdn.com/b/flow/archive/2011/08/16/how-to-save-wf4-workflow-definition-to-image-using-code.aspx
let’s look at how to generate an image of the workflow definition using the standard mechanism of WPF. After all, workflow designer canvas is a WPF control.
BitmapFrame CreateWorkflowDefinitionImage()
{
const double DPI = 96.0;
// this is the designer area we want to save
Visual areaToSave = ((DesignerView)VisualTreeHelper.GetChild(
this.workflowDesigner.View, 0)).RootDesigner;
// get the size of the targeting area
Rect size = VisualTreeHelper.GetDescendantBounds(areaToSave);
RenderTargetBitmap bitmap = new RenderTargetBitmap((int)size.Width, (int)size.Height,
DPI, DPI, PixelFormats.Pbgra32);
bitmap.Render(areaToSave);
return BitmapFrame.Create(bitmap);
}
The above C# method is very straightforward. Just get the workflow diagram part of the workflow designer and create an in-memory image of it using some WPF API. The next thing is simple: create a file and save the image.
void SaveImageToFile(string fileName, BitmapFrame image)
{
using (FileStream fs = new FileStream(fileName, FileMode.Create))
{
BitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(image));
encoder.Save(fs);
fs.Close();
}
}
At last, let’s try to invoke the above 2 methods in the OnInitialized() method to hook it up and then close the application.
protected override void OnInitialized(EventArgs e)
{
// ...
this.SaveImageToFile("test.jpg", this.CreateWorkflowDefinitionImage());
Application.Current.Shutdown();
}

iTextSharp: Why when adding a image to a pdf page the text font is different?

I use Helvetica font and 14 px size for text. The problem is that if a page does not have any image on it the text is very clear, but in a page with at least 1 image the text is getting a little bold. You can see what I mean in images below:
* Without image on page
* With image on page
The correct font is the one that appear in picture #1. How to make all pages have the same font even if the page contains an image or not?
Thanks.
Sample code:
Document document = new Document(PageSize.LETTER);
document.SetMargins(docMargin, docMargin, docMargin, 25);
writer = PdfWriter.GetInstance(document, new FileStream(filename, FileMode.Create));
document.Open();
Font defaultFont = FontFactory.GetFont("Helvetica", 7.8, Font.NORMAL, new Color(75, 75, 75));
document.Add(new Paragraph("Lorem ipsum lorem ipsum lorem ipsum", defaultFont));
document.Add(Chunk.NEWLINE);
Image img = Image.GetInstance("my png image path");
document.Add(img);
document.Close();
I was finally able to reproduce your problem. The first PNG that I tested with which didn't reproduce your problem I created from Photoshop and used the Save For Web command. The second PNG that I tested and was able to reproduce your problem I created from MSPAINT.EXE. I tried various combinations within Save For Web and none of them have the same problem as Paint.
According to this thread from the official iText mailing list it appears to be something about the color profile of the image.
What are you seeing is the impact of newly placed transparency into a
PDF that had not previously contained it, when consideration isn't
given for the blending colorspace of the final output document.
You have an RGB document that upon adding transparency is forced into
CMYK due to lack of explicit blending space. If you were to specify
RGB as your explicit blending space at the same time you added your
transparency, all would be well.
One thing they recommend is setting the following property on your PdfWriter before adding anything:
writer.RgbTransparencyBlending = true;
When I do it I still see a very minor shift but no where near as pronounced as without it.
This isn't an answer, I just need to be able to post code.
I'm unable to reproduce your results but if I were to guess it has something to do with your PDF renderer. You can confirm this by zooming in on the text, does it look the same when zoomed in? If so, that's your renderer trying to apply visual hints to a print document. If not, can you post a simplified version of your code that does this? Does this do this for all images or just one specific one? How are you creating your text, with Paragraphs, Tables, HTML parsing or something else? What version of iTextSharp are you using?
Below is a full working WinForms C# 2010 targeting iTextSharp 5.1.2.0 that creates a two page PDF. The first page has just text and the second page has text followed by an image loaded from the desktop. On my machine, using Adobe Acrobat Pro 9.1.3 I don't see any difference in fonts when I view it on screen.
using System;
using System.IO;
using System.Windows.Forms;
using iTextSharp.text;
using iTextSharp.text.pdf;
namespace WindowsFormsApplication1 {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
string pdfFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test.pdf");
string imgFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test.png");
using (FileStream fs = new FileStream(pdfFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
using (Document doc = new Document(PageSize.LETTER)) {
using (PdfWriter writer = PdfWriter.GetInstance(doc, fs)) {
doc.Open();
BaseFont bf = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.CP1250, BaseFont.NOT_EMBEDDED);
iTextSharp.text.Font f = new iTextSharp.text.Font(bf, 14);
doc.NewPage();
doc.Add(new Paragraph("This is a test", f));
doc.NewPage();
doc.Add(new Paragraph("This is a test", f));
iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(imgFile);
img.ScaleAbsolute(100, 100);
doc.Add(img);
doc.Close();
}
}
}
this.Close();
}
}
}

Images turning sideways/upside down after being uploaded via PhoneGap (iOS)

Not sure what would be causing this, but when I upload some images to my remote server via FileTransfer(), the images sometimes show up either sideways or upside down. However, when I view the images locally on the iPhone, they are positioned in the correct way.
For example, when I select an image like this to upload: http://sharefa.st/view/WBe2QNSK8r8z
It will turn out like this: http://sharefa.st/view/EWdW1Z4G8r8z
I am using the local path to transfer the file, so I don't understand why the image would rotate "randomly".
Here is my upload function:
function uploadPhoto() {
var options = new FileUploadOptions();
options.fileKey = 'file';
options.fileName = imgURI.substr(imgURI.lastIndexOf('/')+1);
options.mimeType = 'image/jpeg';
var params = new Object();
if(logged_in == true) {
params.unique_id = app_unique_id;
params.secret_key = user_secret_key;
}
options.params = params;
loadingStart();
var ft = new FileTransfer();
ft.upload(imgURI, 'http://' + remote_server + '/API/upload', uploadDetails, fail, options);
}
imgURI value looks like this:
file://localhost/var/mobile/Applications/<snip>/tmp/photo_015.jpg
Any insight is appreciated.
Thanks to Humanoidism pointing out that the issue was in fact with the iPhone, and the way it stored images, I was able to figure out a solutuion.
To upload photos in the correct orientation you must add the correctOrientation setting to the options array in getPicture(), and set it to true.
Here are two examples:
function capturePhoto() {
navigator.camera.getPicture(onPhotoDataSuccess, onFail, { quality: 30, correctOrientation: true });
}
function getPhoto(source) {
navigator.camera.getPicture(onPhotoURISuccess, onFail, { quality: 30,
destinationType: destinationType.FILE_URI,
sourceType: source,
correctOrientation: true });
}
The problem is not PhoneGap but iPhone. The iPhone was designed to be used as a wide lens camera. Turn the phone sideways when taking pictures or capturing video if you intend to view them on desktop. Your phone will display them correctly, because it "knows" how you took them, but the computer that you're viewing it on dosen't.
What you could do to prevent this is to rotate the picture before the upload. This is not a recommended fix but at least people on desktop computers will be able to see it. Though when viewing them on iPhone they'll be rotated - maybe a check for mobile devices wether or not to rotate the image could come in handy - but still again, not recommended.

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