I'm making a game in which there are different ellipses and at a time i've to select only one ellipse and move it to the position where I press the pointer. So how can I do that? (Syntax Please!).
There are to main input events you can use - PointerMoved and ManipulationDelta. Just handle one of these events and move the ellipse based on information you get. The sender of the event is the UIElement (i.e. Ellipse) that was dragged.
If it's ManipulationDelta - you also need to specify ManipulationMode - e.g. ManipulationMode="TranslateX,TranslateY,TranslateIntertia", but then you can just move the Ellipse by eventArgs.Delta.Translation.X/Y on each event.
With PointerMoved - you'll also need to check which pointer moved, whether it's pressed, track whether PointerPressed on that pointer was last raised on your Ellipse etc. I wouldn't go there.
You can move a UIElement using a few methods.
If it's in a Grid - you can move it by dx, dy by setting
ellipse.Margin = new Thickness(
ellipse.Margin.Left + dx,
ellipse.Margin.Top + dy,
ellipse.Margin.Right - dx,
ellipse.Margin.Bottom - dy);
If it's in a Canvas - you can move it like this:
var x = Canvas.GetLeft(ellipse);
var y = Canvas.GetTop(ellipse);
Canvas.SetLeft(x + dx);
Canvas.SetTop(y + dy);
Otherwise - if your ellipse has a RenderTransform - e.g. TranslateTransform - you would do it like this:
var ellipse = (Ellipse)sender;
var tt = (TranslateTransform)ellipse.RenderTransform;
tt.X += dx;
tt.Y += dy;
Related
I'm trying to make a midi-editor in processing and I need to have rectangular cells that you can click on to add a note there.
So far I've done googling but haven't found a result. What happens is when you click the further down the less accurate it gets.
I don't know what is going wrong and I've had this problem in the past but couldn't fix it.
Note: The cells are not square.
Example processing code to snap the mouse coordinates to the center of the nearest grid cell (where cell dimensions are defined by rectangle width and height).
int w = 48; // rectangle width
int h = 24; // rectangle height
int snapX = round(mouseX / w) * w + w/2; // '+ w/2' is offset to center of cell
int snapY = round(mouseY / h) * h + h/2; // '+ h/2' is offset to center of cell
I'm using processing, and I'm trying to create a circle from the pixels i have on my display.
I managed to pull the pixels on screen and create a growing circle from them.
However i'm looking for something much more sophisticated, I want to make it seem as if the pixels on the display are moving from their current location and forming a turning circle or something like this.
This is what i have for now:
int c = 0;
int radius = 30;
allPixels = removeBlackP();
void draw {
loadPixels();
for (int alpha = 0; alpha < 360; alpha++)
{
float xf = 350 + radius*cos(alpha);
float yf = 350 + radius*sin(alpha);
int x = (int) xf;
int y = (int) yf;
if (radius > 200) {radius =30;break;}
if (c> allPixels.length) {c= 0;}
pixels[y*700 +x] = allPixels[c];
updatePixels();
}
radius++;
c++;
}
the function removeBlackP return an array with all the pixels except for the black ones.
This code works for me. There is an issue that the circle only has the numbers as int so it seems like some pixels inside the circle won't fill, i can live with that. I'm looking for something a bit more complex like I explained.
Thanks!
Fill all pixels of scanlines belonging to the circle. Using this approach, you will paint all places inside the circle. For every line calculate start coordinate (end one is symmetric). Pseudocode:
for y = center_y - radius; y <= center_y + radius; y++
dx = Sqrt(radius * radius - y * y)
for x = center_x - dx; x <= center_x + dx; x++
fill a[y, x]
When you find places for all pixels, you can make correlation between initial pixels places and calculated ones and move them step-by-step.
For example, if initial coordinates relative to center point for k-th pixel are (x0, y0) and final coordinates are (x1,y1), and you want to make M steps, moving pixel by spiral, calculate intermediate coordinates:
calc values once:
r0 = Sqrt(x0*x0 + y0*y0) //Math.Hypot if available
r1 = Sqrt(x1*x1 + y1*y1)
fi0 = Math.Atan2(y0, x0)
fi1 = Math.Atan2(y1, x1)
if fi1 < fi0 then
fi1 = fi1 + 2 * Pi;
for i = 1; i <=M ; i++
x = (r0 + i / M * (r1 - r0)) * Cos(fi0 + i / M * (fi1 - fi0))
y = (r0 + i / M * (r1 - r0)) * Sin(fi0 + i / M * (fi1 - fi0))
shift by center coordinates
The way you go about drawing circles in Processing looks a little convoluted.
The simplest way is to use the ellipse() function, no pixels involved though:
If you do need to draw an ellipse and use pixels, you can make use of PGraphics which is similar to using a separate buffer/"layer" to draw into using Processing drawing commands but it also has pixels[] you can access.
Let's say you want to draw a low-res pixel circle circle, you can create a small PGraphics, disable smoothing, draw the circle, then render the circle at a higher resolution. The only catch is these drawing commands must be placed within beginDraw()/endDraw() calls:
PGraphics buffer;
void setup(){
//disable sketch's aliasing
noSmooth();
buffer = createGraphics(25,25);
buffer.beginDraw();
//disable buffer's aliasing
buffer.noSmooth();
buffer.noFill();
buffer.stroke(255);
buffer.endDraw();
}
void draw(){
background(255);
//draw small circle
float circleSize = map(sin(frameCount * .01),-1.0,1.0,0.0,20.0);
buffer.beginDraw();
buffer.background(0);
buffer.ellipse(buffer.width / 2,buffer.height / 2, circleSize,circleSize);
buffer.endDraw();
//render small circle at higher resolution (blocky - no aliasing)
image(buffer,0,0,width,height);
}
If you want to manually draw a circle using pixels[] you are on the right using the polar to cartesian conversion formula (x = cos(angle) * radius, y = sin(angle) * radius).Even though it's focusing on drawing a radial gradient, you can find an example of drawing a circle(a lot actually) using pixels in this answer
video game link
I'm trying to make a game (see link above) , and I need to have the stick rotate around himself to maintain the orientation face to center of the circle.
this is how I declare the Sprite, and how I move it around the circle:
declaration:
line = new Sprite(new Texture(Gdx.files.internal("drawable/blockLine.png")));
line.setSize(140, 20);
lineX = Gdx.graphics.getWidth()/2 - line.getWidth()/2;
lineY = (Gdx.graphics.getHeight()/2 - line.getHeight()/2) + circle.getHeight()/2;
movement:
Point point = rotatePoint(new Point(lineX, lineY), new Point(Gdx.graphics.getWidth()/2, Gdx.graphics.getHeight()/2), angle+= Gdx.graphics.getDeltaTime() * lineSpeed);
line.setPosition(point.x, point.y);
rotatePoint function:
Point rotatePoint(Point point, Point center, double angle){
angle = (angle ) * (Math.PI/180); // Convert to radians
float rotatedX = (int) (Math.cos(angle) * (point.x - center.x) - Math.sin(angle) * (point.y-center.y) + center.x);
float rotatedY = (int) (Math.sin(angle) * (point.x - center.x) + Math.cos(angle) * (point.y - center.y) + center.y);
return new Point(rotatedX,rotatedY);
}
Any sugestions ?
I can't test right now but I think the rotation of the line should simply be:
Math.atan2(rotatedPoint.getOriginX() - middlePoint.getOriginX(), rotatedPoint.getOriginY() - middlePoint.getOriginY()));
Then you'll have to adjust rad to degrees or whatever you'll use. Tell me if it doesn't work!
I would take a different approach, I just created a method that places n Buttons around a click on the screen. I am using something that looks like this:
float rotation; // in degree's
float distance; //Distance from origin (radius of circle).
vector2 originOfRotation; //Center of circle
vector2 originOfSprite; //Origin of rotation sprite we are calculating
Vector2 direction = new vector2(0, 1); //pointing up
//rotate the direction
direction.rotate(rotation);
// add distance based of the direction. Warning: originOfRotation will change because of chaining method.
// use originOfRotation.cpy() if you do not want to init each frame
originOfSprite = originOfRotation.add(direction.scl(distance));
Now you have the position of your sprite. You need to increment rotation by x each frame to have it rotate. If you want the orientation of the sprite to change you can use the direction vector, probably rotated by 180 again. Efficiency wise I'm not sure what the difference would be.
I love the way Sublime text shows it's product demo on it's home page:
http://www.sublimetext.com/
How can I create a similar demo? All I note is that it is a Canvas element.
Sorry if it's sounds as a basic question. I see it's made on Canvas. Any leads or help in this regard is highly appreciate?
They are using delays and parts of images such as this one (look at the bottom part of the image):
and specify what (rectangular) part of each image renders when, making it look like an animation.
It's a typical texture atlas.
This is the list of the images:
"anim/rename2_packed.png",
"anim/days_169_packed.png",
"anim/command_palette_packed.png",
"anim/goto_anything_packed.png",
"anim/goto_anything2_packed.png",
"anim/regex_packed.png"
And this is how they specify the delay and the image pieces
{"delay":1811,"blit":[[0,0,800,450,0,0]]},
{"delay":48,"blit":[[0,450,400,344,200,36],[66,982,63,15,0,36]]},
{"delay":798,"blit":[]}, etc...
As you see, delay is the time in milliseconds, and blit looks like parameters for drawImage - srcX, srcY, width, height, destX, destY.
Each of the "screens" is kept as a separate variable, like command_palette_timeline, days_169_timeline, goto_anything_timeline, etc. Each containing delay/blit array of objects like the one from the paragraph above.
The actual render code is pretty straightforward, they follow each step in each timeline, with delays between them, and each step is rendered like this:
for (j = 0; j < blits.length; ++j)
{
var blit = blits[j]
var sx = blit[0]
var sy = blit[1]
var w = blit[2]
var h = blit[3]
var dx = blit[4]
var dy = blit[5]
ctx.drawImage(img, sx, sy, w, h, dx, dy, w, h)
}
I am trying to implement transform methods to rotate and resize a movieclip at runtime and I have a problem when recalculating the rotation to follow the mouse.
I have a squared movieclip and a rotator object (a circle) at the right bottom corner of the square where I am listening for mouse events and on mouse move I do this:
_rotation = -(Math.atan2((event.stageX - this.x ), (event.stageY - this.y ))) * 180/Math.PI;
this.rotation = rotation + 45;//this is because my rotator object is on right,bottom corner
this works perfect as long as I don´t modify the width or height of the object but if I do modify then there is a small "jump" on the rotation of the object that I am not able of avoid.
I know this is due event.stageX and even.stageY are different as the rotator object, the one with the mouse listener, has moved after the resize event but no clue how to avoid the "jump".
Please excuse my bad English
You need to rotate the object around its center.
/**
* Rotates the object based on its center
* Parameters: #obj => the object to rotate
* # rotation => angle to rotate
* */
public function RotateAroundCenter(obj:Object, rotation:Number):void
{
var bound:Rectangle = new Rectangle();
// get the bounded rectangle of objects
bound = obj.getRect(this);
// calculate mid poits
var midx1:Number = bound.x + bound.width/2;
var midy1:Number = bound.y + bound.height/2;
// assign the rotation
obj.rotation = rotation;
// assign the previous mid point as (x,y)
obj.x = midx1;
obj.y = midy1;
// get the new bounded rectangle of objects
bound = obj.getRect(this);
// calculate new mid points
var midx2:Number = bound.x + bound.width/2;
var midy2:Number = bound.y + bound.height/2;
// calculate differnece between the current mid and (x,y) and subtract
//it to position the object in the previous bound.
var diff:Number = midx2 - obj.x;
obj.x -= diff;
diff = midy2 - obj.y;
obj.y -= diff;
}
Usage:
_rotation = -(Math.atan2((event.stageX - this.x ), (event.stageY - this.y ))) * 180/Math.PI;
RotateAroundCenter(this, rotation + 45);
Check this link