I'm creating a desktop application in JavaFX which enables the user to search for people in different categories. There is a screen which shows each category as a tile with an image (Aspect ratio 1:1). When you click on a tile it opens another page and the image from the tile should now be displayed as the background image (Aspect ratio 16:9). The images are selected by an admin user, so it must be cropped because it could be too large, have a wrong aspect ratio and so on.
I wonder how to set up an easy way to enable the admin user to select the picture he wants, without having to crop the image twice (once as 1:1 and once as 16:9). I thought about crop only to 1:1 and then for displaying as 16:9 just zooming the picture, but this leads to bad quality if the resolution isn't high enough.
For cropping I'm referencing to this post from Roland:
How to make a Javafx Image Crop App
For background images you can simply specify that the image should cover the Region.
ImageView allows you to specify a viewport allowing you to specify the region of the Image that should be displayed. If chosen accordingly this does the croping for you.
The following code uses the same ratio for both for simplicity's sake:
#Override
public void start(Stage primaryStage) {
final Image image = new Image(URL);
// size to use for both nodes
double targetHeight = 400;
double targetWidth = targetHeight * 16 / 9;
ImageView imageView = new ImageView(image);
imageView.setFitWidth(targetWidth);
imageView.setFitHeight(targetHeight);
// calculate viewport
imageView.setViewport((image.getHeight() / targetHeight < image.getWidth() / targetWidth)
? new Rectangle2D(0, 0, image.getHeight() / targetHeight * targetWidth, image.getHeight())
: new Rectangle2D(0, 0, image.getWidth(), image.getWidth() / targetWidth * targetHeight));
Region backgroundRegion = new Region();
backgroundRegion.setPrefSize(targetWidth, targetHeight);
backgroundRegion.setBackground(new Background(
new BackgroundImage(
image,
BackgroundRepeat.NO_REPEAT,
BackgroundRepeat.NO_REPEAT,
BackgroundPosition.CENTER,
new BackgroundSize(0, 0, false, false, false, true) // cover
)));
HBox root = new HBox(imageView, backgroundRegion);
root.setFillHeight(false);
root.setPadding(new Insets(20));
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}
Related
I'm using the following code snippet to record and get an image from a canvas. The image shows fuzzy on some devices.
setLayerBuffer(int layerID) async {
recorder = new ui.PictureRecorder();
canvas2 = new Canvas(recorder, canvasRect); //canvasRect is the drawing area
for (var myLayer in layers)
if (myLayer.id == layerID) {
if (myLayer.buffer != null) {
canvas2.drawImage(myLayer.buffer, new Offset(0.0, 0.0), Paint());
}
doPaint(canvas2, 1); //this will draw on canvas2
break;
}
var picture = recorder.endRecording();
buffer = await picture.toImage(
canvasRect!.width.round(), canvasRect!.height.round());
setBuffer(layerID, buffer!); // store image as buffer in layer
paintController.myNotifyListeners(); //paint the main canvas wiht buffers of layers
}
According to this https://github.com/flutter/flutter/issues/17782, the canvas created from scratch is not being set with device pixel ratio unlike the canvas created by CustomPaint.
I did try to set canvas scale with device pixel ratio as suggested by the above link. However, the image disappears after setting the scale. How do I set the canvas to use the device pixel ratio ?
I'm talking photo in my application. After I take it, on next screen in layout I want it be automatically cropped like in image.
But I'm constantly lose the boundaries of the photo and I have strange borders (indicated by RED in the image).
Here is my code:
Android code
private void NewElement_OnDrawBitmap(object sender, EventArgs e)
{
if (this.ViewGroup != null)
{
//get the subview
Android.Views.View subView = ViewGroup.GetChildAt(0);
int width = subView.Width;
int height = subView.Height;
//create and draw the bitmap
Bitmap b = Bitmap.CreateBitmap(width, height, Bitmap.Config.Argb8888);
Canvas c = new Canvas(b);
ViewGroup.Draw(c);
//save the bitmap to file
bytes = SaveBitmapToFile(b);
}
}
iOS code
UIGraphics.BeginImageContextWithOptions(this.Bounds.Size, true, 0);
this.Layer.RenderInContext(UIGraphics.GetCurrentContext());
var img = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
using (NSData imageData = img.AsPNG())
{
bytes = new Byte[imageData.Length];
System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, bytes, 0, Convert.ToInt32(imageData.Length));
}
private byte[] SaveBitmapToFile(Bitmap bm)
{
MemoryStream ms = new MemoryStream();
bm.Compress(Bitmap.CompressFormat.Png, 100, ms);
return ms.ToArray();
}
}
From your shared code, you're not doing any cropping, so your app just put your origin picture into the view, and the border you mentioned, is probably the background of your view.
And your project code, I saw you added
Bitmap bitmap = Bitmap.CreateBitmap(b, 0, 0, (98 * width) / 100, (82 * height) / 100);
Yes this is cropping the picture, but this just crop the image from top-left corner to 98% width and 82% height. much like
If you want to crop the picture into a square focused in center, you can simply:
int offset = (height - width) / 2;
Bitmap bitmap = Bitmap.CreateBitmap(b, 0, offset, width, height- offset);
But if you want to do more operations on Image like move/zoom... and then crop, I'd like to suggest you turn to existing solutions like FFImageLoading or Syncfusion. Or you'll have to calculate all the move/zoom data to do the crop.
I want to merge two images,one image is of 300x300 and other is 100x100, First i have created a canvas and then i created two images which i have added to the both the images to canvas and the canvas is added to the content panel, then i created a writeablebitmap and render the canvas and created a method savejpeg which saves the image to isolated stoarage,but isolated storage is not showing the whole image it save a black screen.
First i created a canvas through code set its height width and background color then i created two images programmatically which i have added to the canvas and then canvas is added to the contentpanel
my code is:
public void CreateImage()
{
Canvas canvas = new Canvas();
canvas.Height = 400;
canvas.Width = 400;
canvas.Background = new SolidColorBrush(Colors.Red);
Image img1 = new Image();
img1.Source = (ImageSource)new ImageSourceConverter().ConvertFromString("Image/Desert.jpg");
img1.Height = 300;
img1.Width = 300;
img1.Margin = new Thickness(0, 10, 0, 0);
Image img2 = new Image();
img2.Source = (ImageSource)new ImageSourceConverter().ConvertFromString("Image/Jellyfish.jpg");
img2.Height = 50;
img2.Width = 50;
img2.Margin=new Thickness(0,10,300,0);
canvas.Children.Add(img1);
canvas.Children.Add(img2);
ContentPanel.Children.Add(canvas);
WriteableBitmap wb = new WriteableBitmap(400, 400);
wb.Render(canvas, new MatrixTransform());
MemoryStream ms = new MemoryStream();
wb.SaveJpeg(ms,400,400,0,100);
using (var isoFileStream = new IsolatedStorageFileStream("myPicture.jpg", FileMode.OpenOrCreate, IsolatedStorageFile.GetUserStoreForApplication()))
{
wb.SaveJpeg(isoFileStream, 400, 400, 0, 100);
}
}
When i save the image then i am getting a black screen in isolated storage.
How to save both images on canvas?
Like Stephan said, I think you are not getting the image to your source. Any way I created a sample application for you. In that you can find two partitions, you can add image to that by double tapping on the container. After that try save and check your saved image. I tested the app and every thing is working for me. Still you face any kind of issues please leave a comment.
https://www.dropbox.com/s/1vjbbou96w0r15r/SaveImageApp.zip
Please check weather you are getting image or not to image source. If you are getting the image; try this method to take snapshot from control and save that to Iso store.
http://stackoverflow.com/questions/13837148/how-can-i-take-a-screenshot-full/13990649#13990649
I'm trying to scale an image that has already been draw into canvas.
This is the code:
var canvas = document.getElementById('splash-container');
var context = canvas.getContext('2d');
var imageObj = new Image();
imageObj.onload = function() {
// draw image at its original size
context.drawImage(imageObj, 0, 0);
};
imageObj.src = 'images/mine.jpeg';
// Now let's scale the image.
// something like...
imageObj.scale(0.3, 0.3);
How should I do?
You're thinking about it wrong. Once you've drawn the image onto the canvas it has no relationship to the imageObj object. Nothing you do to imageObj will affect what's already drawn. If you want to scale the image, do in the drawImage function:
drawImage(imgObj, 0, 0, imgObj.width * 0.3, imgObj.height * 0.3)
If you want to animate the scaling or are looking to achieve some other effect which requires you to draw the image at full size initially you'll have to first clear it before drawing the scaled down image.
What robertc says is correct, but if you really wanted to scale an image on a canvas after drawing it for some reason, you could just scale the whole canvas using the CSS width/height properties and that would scale the image without having to redraw it.
I am working on an app in which images are flying on the Screen.
I need to implement:
Hold onto any of the flying images on Tap
Drag the image to certain position of the user's choice by letting the user hold it.
Here is another easy way to do dragging.
Just draw your image (Texture2d) with respect to a Rectangle instead of Vector2.
Your image variables should look like this
Texture2d image;
Rectangle imageRect;
Draw your image with respect to "imageRect" in Draw() method.
spriteBatch.Draw(image,imageRect,Color.White);
Now in Update() method handle your image with single touch input.
//Move your image with your logic
TouchCollection touchLocations = TouchPanel.GetState();
foreach(TouchLocation touchLocation in touchLocations)
{
Rectangle touchRect = new Rectangle
(touchLocation.Position.X,touchLocation.Position.Y,10,10);
if(touchLocation.State == TouchLocationState.Moved
&& imageRect.Intersects(touchRect))
{
imageRect.X = touchRect.X;
imageRect.Y = touchRect.Y;
}
//you can bring more beauty by bringing centre point
//of imageRect instead of initial point by adding width
//and height to X and Y respectively and divide it by 2
There's a drag-and-drag example in XNA here: http://geekswithblogs.net/mikebmcl/archive/2011/03/27/drag-and-drop-in-a-windows-xna-game.aspx
When you load your image in, you'll need a BoundingBox or Rectangle Object to control where it is.
So, in the XNA app on your phone, you should have a couple of objects declared for your texture.
Texture2D texture;
BoundingBox bBox;
Vector2 position;
bool selected;
Then after you load your image content, keep your bounding box updated with the position of your image.
bBox.Min = new Vector3(position, 1.0f);
bBox.Max = new Vector3(position.X + texture.Width, position.Y + texture.Height, 0f);
Then also in your update method, you should have a touch collection initialized to handle input from the screen, get the positions of the touch collection, loop through them and see if they intersect your boundingbox.
foreach (Vector2 pos in touchPositions)
{
BoundingBox bb = new BoundingBox();
bb.Min = new Vector3(pos, 1.0f);
bb.Max = new Vector3(pos, 0f);
if (bb.Intersects(bBox)
{
if (selected)
{
//do something
}
else
{
selected = true;
}
}
}
From there, you have whether your object is selected or not. Then just use the gestures events to determine what you want to do with your texture object.