Develop Reference

Move a matrix to the top right corner using pdfbox

Context :
I'm fairly new generating pdf and i'm scaling a matrix but my issue is that when the matrix gets scaled it then put my scaled matrix to the bottom left corner of the pdf.
My issue :
My problem is that actually when i cale my pdf it get stuck at the bottom left corner of the page and i can't find a way to put it on the top right corner whatever of the size of the scaled matrix.
My code :
float titleWidth = font.getStringWidth(title) / 1000 * fontSize;
float titleHeight = font.getFontDescriptor().getFontBoundingBox().getHeight() / 1000 * fontSize;
float width = page.getMediaBox().getWidth();
float height = page.getMediaBox().getHeight();
float ratio = Math.min(maxWidth/width, maxHeight /height);
float scaledWidth = width * ratio;
float scaledHeight = height * ratio;
page.setCropBox(PDRectangle.A4);
matrix.scale(sx = width / scaledWidth, height / scaledHeight);
contentStream.transform(matrix);
contentStream.beginText();
contentStream.newLineAtOffset(((page.getMediaBox().getWidth() - titleWidth) / 2), page.getMediaBox().getHeight() - marginTop - titleHeight);
contentStream.setFont(font, (float) (fontSize));
contentStream.showText(title);
contentStream.endText();
ByteArrayOutputStream os = new ByteArrayOutputStream();
contentStream.close();
document.save(os);
document.close();
return os.toByteArray();
This is a screenshoot of were the scaled matrix actually is (in case my explanation are not clean) :

Draw text directly under a specified bitmap

p.setColor(Color.parseColor("#D32F2F"));
RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(), (float) itemView.getRight(), (float) itemView.getBottom());
c.drawRect(background, p);
icon = getBitmapFromVectorDrawable(MainActivity.this, R.drawable.ic_clear);
RectF icon_dest = new RectF((float) itemView.getRight() - 2 * width, (float) itemView.getTop() + width, (float) itemView.getRight() - width, (float) itemView.getBot
c.drawBitmap(icon, null, icon_dest, p); //[1]
p.setTextSize(50);
p.setColor(Color.WHITE);
c.drawText("Cancel",*/Insert x and y here*/,p);
So far I have that.
I'm trying to drawText directly under the bitmap I drawed. ([1]). However I'm not sure how to get the coordinates of the bitmap and adjust it so that it's centered below it.
The above image is what I'm trying to achieve. Contents of the app has been censored.
In conclusion, how do I get the coordinates for the text that I'm trying to get?
I'm using onChildDraw method of the ItemTouchHelper for a RecyclerView.

You can use paint.getTextBounds() to get the bounds of the text that you are about to draw on the canvas. Once you get the bounds of the text, you can calculate the position to draw the text based on the icon's position.
Edit:
This aligns the text below the icon at the X position same as the icon:
float textX = icon_dest.left;
float textY = icon_dest.bottom + some_padding;
canvas.drawText("Cancel", textX, textY, textPaint);
This aligns the center of the icon and the center of the text in a same vertical line:
Rect textBounds = new Rect();
textPaint.getTextBounds("Cancel", 0, length, textBounds);
float iconCenterX = icon_dest.left + (icon_dest.width() / 2);
float textHalfWidth = (textBounds.right - textBounds.left) / 2;
float textX = iconCenterX - textHalfWidth;
float textY = icon_dest.bottom + somePadding
canvas.drawText("Cancel", textX, textY, textPaint);

Google maps custom marker android

I'm making a public transportation map based on Google Maps service for Android. The map should contain a lot of markers (over 300) and they should resize when the map is zooming in and out (scale). Right now the markers just overlap each other, is there a way to create custom markers like this?
I have tried myself, but have had no success. With android-map-utils library (https://github.com/googlemaps/android-maps-utils) markers now look better, but they aren't resizeable and look different.
Criteria:
- Markers contain a dot that points on needed location and text on right or left side of dot
- Markers should resize with map.

using bitmapscale
Bitmap markerBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon_marker,options);
markerBitmap = SubUtils.scaleBitmap(markerBitmap, 70, 70);
then set it to your Markeroptions
MarkerOptions marker = new MarkerOptions().icon(BitmapDescriptorFactory.fromBitmap(markerBitmap));
Marker mark = googleMap.addMarker(marker);
EDIT
here is scaleBitmap method
public static Bitmap scaleBitmap(Bitmap bitmap, int newWidth, int newHeight) {
Bitmap scaledBitmap = Bitmap.createBitmap(newWidth, newHeight, Bitmap.Config.ARGB_8888);
float scaleX = newWidth / (float) bitmap.getWidth();
float scaleY = newHeight / (float) bitmap.getHeight();
float pivotX = 0;
float pivotY = 0;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(scaleX, scaleY, pivotX, pivotY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(bitmap, 0, 0, new Paint(Paint.FILTER_BITMAP_FLAG));
return scaledBitmap;
}

The Projection Matrix Does More than Scaling, Right?

As I have it understood, a projection matrix scales a polygon depending on how far away or close it is from the camera. Though I might be completely wrong. My question is, how does the projection matrix "know" to show the sides of the following cube, as the camera moves, when the matrix is only supposed "scale" polygons?
Notice in the image, the cube is off to the right side of the screen, by moving the camera to the left. If the camera is moved in the opposite direction (to the right) in order to center the cube, the side of the cube will disappear as expected.
Here is my matrix code:
private void createProjectionMatrix(){
float aspectRatio = (float) Display.getWidth() / (float) Display.getHeight();
float y_scale = (float) ((1f / Math.tan(Math.toRadians(FOV/2f))) * aspectRatio);
float x_scale = y_scale / aspectRatio;
float frustum_length = FAR_PLANE - NEAR_PLANE;
projectionMatrix = new Matrix4f();
projectionMatrix.m00 = x_scale;
projectionMatrix.m11 = y_scale;
projectionMatrix.m22 = -((FAR_PLANE + NEAR_PLANE) / frustum_length);
projectionMatrix.m23 = -1;
projectionMatrix.m32 = -((2 * NEAR_PLANE * FAR_PLANE) / frustum_length);
projectionMatrix.m33 = 0;
}

The function of a projection matrix (in the context of graphics APIs, such as OpenGL) is to transform vertex positions from view-space into clip-space.
Clip space is generally a unit box (although in D3D it's a half-unit box). If a vertex position after being transformed into clip-space does not lie within that unit box, then it is clipped. This is essentially how the system "knows" the cube is visible on the screen.

how to use SpriteBatch draw method

SpriteBatch batcher = new SpriteBatch();
batcher.draw(TextureRegion region,
float x,
float y,
float originX,
float originY,
float width,
float height,
float scaleX,
float scaleY,
float rotation)
What is the meaning of originX, originY, scaleX, scaleY, rotation? Also can you please give me an example of their use?

Why don't you look into docs ?
As stated in docs, origin is bottom left corner, originX, originY are offsets from this origin.
For example if you want object rotate around his center, you will do this.
originX = width/2;
originY = height/2;
By specifing scaleX, scaleY, you scale the image, if you want to make Sprite 2x larger, you will set both scaleX and scaleY to number 2.
rotation specifies rotation around origin in degrees.
This code snippet draws texture rotated by 90 degrees around its center
SpriteBatch batch = new SpriteBatch();
Texture texture = new Texture(Gdx.files.internal("data/libgdx.png"));
texture.setFilter(TextureFilter.Linear, TextureFilter.Linear);
int textureWidth = texture.getWidth();
int textureHeight = texture.getHeight();
float rotationAngle = 90f;
TextureRegion region = new TextureRegion(texture, 0, 0, textureWidth, textureHeight);
batch.begin();
batch.draw(region, 0, 0, textureWidth / 2f, textureHeight / 2f, textureWidth, textureHeight, 1, 1, rotationAngle, false);
batch.end();
or take a look at tutorial here.