Im using the following code to write text on rectangle.
public static void drawRectangleAndLabelOnPreview(Mat img, Rect face, String label) {
Imgproc.putText(img, label, face.tl(), Core.FONT_HERSHEY_SIMPLEX, FONT_SIZE, FACE_RECT_COLOR, FONT_THICKNESS);
}
I want the rectangle on bottom but it is still in the top. How can I be able to put it in bottom left?
Set Rect face coordinates to bottom left position where you want to put text in the image.
Suppose w and h are width and height of your text box and r and c are number of rows and columns in the image respectively. Then, set face x, y values as:
face.x = 0;
face.y = r - h - 1;
These values are for example if you want to set box on bottom left position. You can change if you want to change position.
Related
I'm trying to learn more and trying to create a basic number generator where on a click of a button a number is generated between 1 and 90 and that number is then crossed out on an image of a board which has numbers from 1 to 90 with an image of x.
I have thought of creating 90 image views with the x image and giving them tags and making them appear when the number has been generated but this method is redundant and not efficient. I'm unable to think of new methods to solve this.
Instead of generating 90 images. You can place a view of X over it and when the desired number is generated makes the X visible for that image.
The code for generating X is.
public class DrawX extends View {
#Override
public void onDraw(Canvas canvas) {
float width = getMeasuredWidth();
float height = getMeasuredHeight();
Paint paint = new Paint();
paint.setColor(Color.RED);
canvas.drawLine(0,0,width,height,paint);
canvas.drawLine(width,0,0,height,paint);
}
}
You can adjust height weight according to your need.
I have a custom view that extends relative layout. In the dispatchDraw method I draw lines and images inside a for loop because i have different start and end points for multiple lines.
I would like to know the easiest way to draw lines with animations from point a to point b in a slow way for example, this animation must be set only for a line that I decide and not for all the others.
I would also like to draw images with animations, I don't want to move the image but I would like to draw the image a little bigger first and then reduce it to the right size, or draw the image from top to bottom. Again this animation must be set only for a image that I decide and not for all the others.
#Override
protected void dispatchDraw(Canvas canvas) {
int width = getWidth();
int height = getHeight();
super.dispatchDraw(canvas);
size = width / (lines);
insideMargin = size / margin;
vMargin = (height - lines * size) / 2f;
canvas.translate(0,vMargin);
for(int x=0; x<lines;x++){
for(int y=0;y<lines;y++){
if(/*a condintion is true*/) {
//draw line with animation, how to do it?
}else{
canvas.drawLine(x * size,
y * size,
(x + 1) * size,
y* size,
paint
);
}
if(/*a condition is true*/) {
//draw bitmap with animation, how to do it?
}else
canvas.drawBitmap(image, src, dest, null);
}
}
}
//i have on touch event that will call invalidate
I think you should use ValueAnimator for your purpose. As I understood, you want to animate values once a touch event occurs. The value returned by the animator must be used for all objects so the animated value should be general as possible. I recommend to use 0 to 1 as float value. You can use this value for the animation. For the bitmap animation, you can define target rectangle start and end size then you can find appropriate size by facilitating the animated fraction value. For the line case, you can use the slope for the animation. I think you already have the line's start and end point so you can use slope and fraction to calculate animated end point.
In a custom view I design a text with drawText function. Now, I would intercepted the click on the text. this my code:
float x = (float)position.getX() + Constants.RADIUS + Constants.OFFSET_OVER_ARCH;
float y = (float)position.getY() ;
for (String line : node.getNode().getLabel().split(Constants.CHAR_SEPARATOR)) {
canvas.drawText(line, x, y, paintSele);
y += paintSele.descent() - paintSele.ascent();
}
Draw rectangle in the text and check if the coordinates of the click is on the rectangle area? This a better solution?
Thanks a lot!
What you can do, is to Paint.measureText(), then Paint.getTextBound() of the text which will fill the inputted Rect with the text's coordinates, and then listen for clicks in that rectangle.
I'm trying to draw a text to the screen and then have a rectangle in the same spot to account for knowing when the user clicks within it (and clicks the text). Problem is when I put the text in one spot on the screen and the rectangle in the same spot, it apparently isn't in the same spot. Is there some setting I need to set somewhere?
private final String[] options = {"Start", "High Scores", "Help", "Quit"};
public void draw(final Canvas g)
{
for (int i = 0; i < options.length; i++)
{
width = HORIZONTALOFFSET * 3 + spaceInvadersTitle.getWidth();
height = GamePanel.getScreenHeight() / 4 - (75 * 2 + TEXT_SIZE) / 2 + i * 75;
rect[i] = new Rect(width, height, width + 325, height + TEXT_SIZE);
g.drawRect(rect[i], paint);
g.drawText(options[i], width, height, paint);
}
}
FYI "width" and "height" are more like x- and y-coords. The horizontal alignment is not the problem - just the vertical. If you'll notice from the code, I'm setting the starting x- and y-coordinates for the drawText and drawRect the same exact position, but that's not how they're showing on the screen. Instead it seems the drawText is using that position as a lowerleft anchorpoint or something like that. Is that how it works? If so, how do I change that?
Also, if you have any suggestions on how to approach listening for when the user clicks on a drawn text, I'm all ears. This is the easiest way I could think of, and how I do it in regular desktop Java.
I need to draw something like this:
I was hoping that this guy posted some code of how he drew his segmented circle to begin with, but alas he didn't.
I also need to know which segment is where after interaction with the wheel - for instance if the wheel is rotated, I need to know where the original segments are after the rotation action.
Two questions:
Do I draw this segmented circle (with varying colours and content placed on the segment) with OpenGL or using Android Canvas?
Using either of the options, how do I register which segment is where?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
EDIT:
Ok, so I've figured out how to draw the segmented circle using Canvas (I'll post the code as an answer). And I'm sure I'll figure out how to rotate the circle soon. But I'm still unsure how I'll recognize a separate segment of the drawn wheel after the rotation action.
Because, what I'm thinking of doing is drawing the segmented circle with these wedges, and the sort of handling the entire Canvas as an ImageView when I want to rotate it as if it's spinning. But when the spinning stops, how do I differentiate between the original segments drawn on the Canvas?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I've read about how to draw a segment on its own (here also), OpenGL, Canvas and even drawing shapes and layering them, but I've yet to see someone explaining how to recognize the separate segments.
Can drawBitmap() or createBitmap() perhaps be used?
If I go with OpenGL, I'll probably be able to rotate the segmented wheel using OpenGL's rotation, right?
I've also read that OpenGL might be too powerful for what I'd like to do, so should I rather consider "the graphic components of a game library built on top of OpenGL"?
This kind of answers my first question above - how to draw the segmented circle using Android Canvas:
Using the code found here, I do this in the onDraw function:
// Starting values
private int startAngle = 0;
private int numberOfSegments = 11;
private int sweepAngle = 360 / numberOfSegments;
#Override
protected void onDraw(Canvas canvas) {
setUpPaint();
setUpDrawingArea();
colours = getColours();
Log.d(TAG, "Draw the segmented circle");
for (int i = 0; i < numberOfSegments; i++) {
// pick a colour that is not the previous colour
paint.setColor(colours.get(pickRandomColour()));
// Draw arc
canvas.drawArc(rectF, startAngle, sweepAngle, true, paint);
// Set variable values
startAngle -= sweepAngle;
}
}
This is how I set up the drawing area based on the device's screen size:
private void setUpDrawingArea() {
Log.d(TAG, "Set up drawing area.");
// First get the screen dimensions
Point size = new Point();
Display display = DrawArcActivity.this.getWindowManager().getDefaultDisplay();
display.getSize(size);
int width = size.x;
int height = size.y;
Log.d(TAG, "Screen size = "+width+" x "+height);
// Set up the padding
int paddingLeft = (int) DrawArcActivity.this.getResources().getDimension(R.dimen.padding_large);
int paddingTop = (int) DrawArcActivity.this.getResources().getDimension(R.dimen.padding_large);
int paddingRight = (int) DrawArcActivity.this.getResources().getDimension(R.dimen.padding_large);
int paddingBottom = (int) DrawArcActivity.this.getResources().getDimension(R.dimen.padding_large);
// Then get the left, top, right and bottom Xs and Ys for the rectangle we're going to draw in
int left = 0 + paddingLeft;
int top = 0 + paddingTop;
int right = width - paddingRight;
int bottom = width - paddingBottom;
Log.d(TAG, "Rectangle placement -> left = "+left+", top = "+top+", right = "+right+", bottom = "+bottom);
rectF = new RectF(left, top, right, bottom);
}
That (and the other functions which are pretty straight forward, so I'm not going to paste the code here) draws this:
The segments are different colours with every run.