How To Crop An Image To a Specific Shape - image

Okay so in SpriteKit I am trying to make a node that has its own physics body and will collide with the player. The problem is the actual image is not a square. It is like a the L tetris block shape. It is a png so the background of the image is blank, however when the character collides with the image it collides with it before the actual image gets to it, because the blank png is still part of the image. So I was wondering if it is possible to cut out that "blank" part of the image so that the character will only collide with the actual image seen.
Here is the code I have for the node:
-(void)makeblock2 {
SKSpriteNode *block2 = [SKSpriteNode spriteNodeWithImageNamed:#"block2.png"];
block2.position = CGPointMake(150,300);
block2.alpha = 1;
block2.size = CGSizeMake(block2.size.width / 2, block2.size.height / 2);
block2.name = #"block2";//how the node is identified later
block2.zPosition = 100;
block2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:CGSizeMake(block2.size.width, block2.size.height)];
block2.physicsBody.categoryBitMask = wallCategory;
[myWorld addChild: block2];
}

Related

Solving Overlapping Images when zooming in Codenameone

I have an imageviewer with a couple images, When i zoom in the first image and wanna see the right side of the image. The folowing image is overlapping the inzooming image. This is very annoying. Is there a way how i can set the zoom in image on the front.
How can i set the zoomed image always on front.
See picture https://i.stack.imgur.com/5f5JZ.jpg
My imageviewer is in a container
Image red ;
red = EncodedImage.create("/HW_Delfzijl_Waddenzee_Oost.jpg");
Image blue = Image.createImage(500, 500, 0xff0000ff);
Image red2 = Image.createImage(500, 500, 0xffff0000);
Image List1[]= new Image [3];
List1[0] = red;
List1[1] = blue;
List1[2] = red2;
iv = new ImageViewer();
iv.setWidth(500);
iv.setHeight(500);
iv.setImageList(new DefaultListModel<>(List1));
Container1 = BoxLayout.encloseY( Kaarten.AuvHW, AdvSpr,iv,
Up,progressbar);
I was able to reproduce this with the following code:
Form hi = new Form("ImageViewer", BoxLayout.y());
Image red = Image.createImage(2000, 800, 0xffff0000);
Image blue = Image.createImage(2000, 500, 0xff0000ff);
ImageViewer viewer = new ImageViewer();
viewer.setImageList(new DefaultListModel<>(red, blue));
hi.add(BoxLayout.encloseY(viewer, new Label("Dummy")));
hi.show();
The problem only happens if I stand on the blue image (the second one) scale it up and then try to move. It doesn't happen when moving from the red image to the blue.
I believe this is due to this method in the ImagaViewer code. Since background isn't painted the old image isn't cleaned up. We need to add a condition that disables that while dragging. I think changing the code in that method to this will fix the problem but it's a bit risky and might trigger flickering:
protected void paintBackground(Graphics g) {
// disable background painting for performance when zooming
if(imageDrawWidth < getWidth() || imageDrawHeight < getHeight() || panPositionX != 0) {
super.paintBackground(g);
}
}
I would suggest filing an issue so we can consider the options here as this isn't trivial. One partial workaround is to use:
viewer.setImageInitialPosition(ImageViewer.IMAGE_FILL);
Which minimizes the impact of the issue.

PsychToolBox GetImage doesn't save using given rect dimensions

I'm trying to save a cropped portion of the screen from my PTB experiment, but the Screen('GetImage',...) function is not working properly. Here is my code:
screenNumber = 0;
% Open screen with grey background
[w, rect] = Screen('OpenWindow', screenNumber,...
background,[], [], [],[],6);
[xCenter, yCenter] = RectCenter(rect);
sideLength = randi([100 175], 1);
baseRect = [0, 0, sideLength, sideLength];
% Center the frame
centeredRect = CenterRectOnPoint(baseRect, xCenter, yCenter);
%dot position
dots.x = randi([ round(xCenter - (sideLength/2))+15 round(xCenter + (sideLength/2))-15], 1, numeral);
dots.y = randi([round(yCenter - (sideLength/2))+15 round(yCenter + (sideLength/2))-15], 1, numeral);
%skipping code to move dots.x into dot_info.position for brevity
Screen('DrawDots',w, dot_info.position, dot_info.size,...
dot_info.colour, [], 2); %dots are drawn to center of screen
Screen('Flip', w);
% Save dot cue
%im = Screen('GetImage', w);
im = Screen('GetImage', w, centeredRect);
imwrite(im, filename);
The issue is that there should be a small square image, centered on the centeredRect rectangle, which contains the dots I've drawn. However, all I get is a correctly sized rectangle without the dots. If I save without passing the centeredRect parameter (commented out line), I get a saved picture of the whole screen, showing the dots in the center - so I know the dots are being drawn. There must be something wrong with the GetImage call and its use of the rect, such that its not saving from the center point of the screen, so i just get the background. When I run this on my monitor it works fine, but on my laptop it does not. Unfortunately I don't have access to my monitor now so I need to get this to work on my laptop. I've checked with a Screens() call and there is only one screen: screen 0 - my laptop screen.
Any help greatly appreciated. Thanks.
SOLVED: I'm not sure why this worked, but I had to multiply the elements in centeredRect by 2. Hoping this helps someone else in future.

How to achieve high quality cropped images from canvas?

I am desperately searching for a good cropping tool. There are a bunch out there, for example:
Croppic
Cropit
Jcrop
The most important thing that I am trying to find is a cropping tool, that crops images without making the cropped image low in resolution. You can hack this by using the canvas tag by resizing the image. This way the image itself stays native, only the representation is smaller.
DarkroomJS was also something near the solution, but, unfortunately, the downloaded demo did not work. I'll try to figure out whats wrong. Does someone know some great alternatives, or how to get the cropped images in...let's say "native" resolution?
Thanks in advance!
You are relying on the cropping tool to provide an interface for the users. the problem is that the image returned is sized to the interface and not the original image. Rather than me sifting through the various API's to see if they provide some way of controlling this behaviour (I assume at least some of them would) and because it is such a simple procedure I will show how to crop the image manually.
To use JCrop as an example
Jcrop provides various events for cropstart, cropmove, cropend... You can add a listener to listen to these events and keep a copy of the current cropping interface state
var currentCrop;
jQuery('#target').on('cropstart cropmove cropend',function(e,s,crop){
currentCrop = crop;
}
I don't know where you have set the interface size and I am assuming the events return the crop details at the interface scale
var interfaceSize = { //you will have to work this out
w : ?,
h : ?.
}
Your original image
var myImage = new Image(); // Assume you know how to load
So when the crop button is clicked you can create the new image by scaling the crop details back to the original image size, creating a canvas at the cropped size, drawing the image so that the cropped area is corectly positioned and returning the canvas as is or as a new image.
// image = image to crop
// crop = the current cropping region
// interfaceSize = the size of the full image in the interface
// returns a new cropped image at full res
function myCrop(image,crop,interfaceSize){
var scaleX = image.width / interfaceSize.w; // get x scale
var scaleY = image.height / interfaceSize.h; // get y scale
// get full res crop region. rounding to pixels
var x = Math.round(crop.x * scaleX);
var y = Math.round(crop.y * scaleY);
var w = Math.round(crop.w * scaleX);
var h = Math.round(crop.h * scaleY);
// Assume crop will never pad
// create an drawable image
var croppedImage = document.createElement("canvas");
croppedImage.width = w;
croppedImage.height = h;
var ctx = croppedImage.getContext("2d");
// draw the image offset so the it is correctly cropped
ctx.drawImage(image,-x,-y);
return croppedImage
}
You then only need to call this function when the crop button is clicked
var croppedImage;
myButtonElement.onclick = function(){
if(currentCrop !== undefined){ // ensure that there is a selected crop
croppedImage = myCrop(myImage,currentCrop,interfaceSize);
}
}
You can convert the image to a dataURL for download, and upload via
imageData = croppedImage.toDataURL(mimeType,quality) // quality is optional and only for "image/jpeg" images

Finding size of images imported at runtime

I am currently loading images at runtime from directories stored in an XML file, and assigning them to RawImage components via the WWW class. While this is working fine, the image is skewed to fit into the new texture size.
I am wondering how to get an image’s original size or aspect ratio so that I can change the size of the image rect to suit. The images to be imported are at varying sizes and therefore the approach used needs to be responsive to the original size of imported images.
Any suggestions would be much appreciated. [Scripting in uJS]
Many thanks in advance, Ryan
function loadContextImage(texLocation : String)
{
if (!imageView.activeSelf)
{
imageView.SetActive(true);
}
var wwwDirectory = "file://" + texLocation; //this will probably need to change for other OS (PC = file:/ [I think?]) - **REVISE**
var newImgTex = new Texture2D(512, 512);
while(true){
var www : WWW = new WWW(wwwDirectory);
yield www;
www.LoadImageIntoTexture(newImgTex);
if (www.isDone){
break; //if done downloading image break loop
}
}
var imageRender : UI.RawImage = imageView.GetComponent.<RawImage>();
imageRender.texture = newImgTex;
}
If you cannot use an Image (for nay valid reasons), you can get the width and height of the texture:
WWW www = new WWW(url);
yield return www;
Texture2D tex = www.texture;
float aspectRatio = tex.height / tex.width;
rawImage.width = width;
rawImage.height = width * aspectRatio;
This should make the rect of the image of the appropriate ratio of the texture.
If you can use Image and preserveAspectRatio, you get it done by Unity. The result is not necessarily the same since it will keep the dimensions of the box and make the Sprite occupies as much space while keeping ratio.

GraphicsView fitInView() very pixelated result when downshrinking

I have searched everywhere and i cannot find any solution after 2 days of trying.
The Problem:
I'm doing an image Viewer with "Fit Image to View" feature. I load a picture of say 3000+ pixels in my GraphicsView (which is a lot smaller ofcourse), scrollbars appear that's good. When i click my btnFitView and executed:
ui->graphicsView->fitInView(scene->sceneRect(),Qt::KeepAspectRatio);
This is down scaling right? After fitInView() all lines are pixelated. It looks like a saw went over the lines on the image.
For example: image of a car has lines, image of a texbook (letters become in very bad quality).
My code sample:
// select file, load image in view
QString strFilePath = QFileDialog::getOpenFileName(
this,
tr("Open File"),
"/home",
tr("Images (*.png *.jpg)"));
imageObject = new QImage();
imageObject->load(strFilePath);
image = QPixmap::fromImage(*imageObject);
scene = new QGraphicsScene(this);
scene->addPixmap(image);
scene->setSceneRect(image.rect());
ui->graphicsView->setScene(scene);
// on_btnFitView_Clicked() :
ui->graphicsView->fitInView(scene->sceneRect(),Qt::KeepAspectRatio);
Just before fitInView(), sizes are:
qDebug()<<"sceneRect = "<< scene->sceneRect();
qDebug()<<"viewRect = " << ui->graphicsView->rect();
sceneRect = QRectF(0,0 1000x750)
viewRect = QRect(0,0 733x415)
If it is necessary i can upload screenshots of original loaded image and fitted in view ?
Am i doing this right? It seems all examples on the Web work with fitInView for auto-fitting. Should i use some other operations on the pixmap perhaps?
SOLUTION
// LOAD IMAGE
bool ImgViewer::loadImage(const QString &strImagePath)
{
m_image = new QImage(strImagePath);
if(m_image->isNull()){
return false;
}
clearView();
m_pixmap = QPixmap::fromImage(*m_image);
m_pixmapItem = m_scene->addPixmap(m_pixmap);
m_scene->setSceneRect(m_pixmap.rect());
this->centerOn(m_pixmapItem);
// preserve fitView if active
if(m_IsFitInView)
fitView();
return true;
}
// TOGGLED FUNCTIONS
void ImgViewer::fitView()
{
if(m_image->isNull())
return;
this->resetTransform();
QPixmap px = m_pixmap; // use local pixmap (not original) otherwise image is blurred after scaling the same image multiple times
px = px.scaled(QSize(this->width(),this->height()),Qt::KeepAspectRatio,Qt::SmoothTransformation);
m_pixmapItem->setPixmap(px);
m_scene->setSceneRect(px.rect());
}
void ImgViewer::originalSize()
{
if(m_image->isNull())
return;
this->resetTransform();
m_pixmap = m_pixmap.scaled(QSize(m_image.width(),m_image.height()),Qt::KeepAspectRatio,Qt::SmoothTransformation);
m_pixmapItem->setPixmap(m_pixmap);
m_scene->setSceneRect(m_pixmap.rect());
this->centerOn(m_pixmapItem); //ensure item is centered in the view.
}
On downshrink this produces good quality. Here are some stats after calling these 2 functions:
// "originalSize()" : IMAGE SIZE = (1152, 2048)
// "originalSize()" : PIXMAP SIZE = (1152, 2048)
// "originalSize()" : VIEW SIZE = (698, 499)
// "originalSize()" : SCENE SIZE = (1152, 2048)
// "fitView()" : IMAGE SIZE = (1152, 2048)
// "fitView()" : PIXMAP SIZE = (1152, 2048)
// "fitView()" : VIEW SIZE = (698, 499)
// "fitView()" : SCENE SIZE = (280, 499)
There is a problem now, after call to fitView() look the size of scene? Much smaller.
And if fitView() is activated, and I now scale the image on wheelEvent (zoomIn/zoomOut), with the views scale function: scale(factor,factor); ..produces terrible result.
This doesn't happen with originalSize() where scene size is equal to image size.
Think of the view as a window into the scene.
Moving the view large amounts, either zooming in or out, will likely create images that don't look great. Rather than the image being scaled as you would expect, the view is just moving away from the scene and doing its best to render the image, but the image has not been scaled, just transformed in the scene.
Rather than using QGraphicsView::fitInView, keep the main image in memory and create a scaled version of the image with QPixamp::scaled, each time FitInView is selected, or the user zooms in / out. Then set this QPixmap on the QGraphicsPixmapItem with setPixmap.
You may also want to think about dropping the scroll bars and allowing the user to drag the image around the screen, which provides a better user interface, in my opinion; though of-course it depends on your requirements.

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