Can't get QGraphicsEllipseItem() to display - pyqt

I can't seem to get a QGraphicsEllipseItem to show up in my view. I am attempting to use it in combination with a QGraphicsLineItem:
# Instantiate the line object:
self.profileLine = QGraphicsLineItem()
self.profileLine.setPen(QPen(Qt.yellow, 1.0))
self.profileLine.setLine(self.StartX, self.StartY, self.StopX, self.StopY)
self.scene.addItem(self.profileLine)
# Instantiate the circle:
self.profileStopHandle = QGraphicsEllipseItem()
self.profileStopHandle.setPen(QPen(Qt.yellow, 1.0))
self.profileStopHandle.setRect(self.StopX, self.StopY, 50, 50)
self.scene.addItem(self.profileStopHandle)
Later, in my mouse move event, I determine the current mouse coordinates, assign them to StopX/StopY and redraw the line from the start point to the new stop point as well as draw the ellipse around the new stop point:
self.profileLine.setLine(self.StartX, self.StartY, self.StopX, self.StopY)
self.profileStopHandle.setPos(self.StopX, self.StopY)
The line shows up fine and behaves just as it should, but no matter what I cannot seem to get the ellipse to draw. I know the point coordinates I'm passing to it are correct because they are the same ones I'm using for the line. The ellipse just never appears as if it was never created in the first place. What am I doing wrong here (it must be something very basic)? Thank you in advance.

The issue was the Z-value (amateur mistake). I brought the ellipse to the foreground and now it is visible:
self.profileStopHandle.setZValue(self.sceneImage.zValue() + 1.0)

Related

Why does rock image does not move alongside the mouse when in motion although I called the node and got its position-Godot Game Engine

I am trying to get my rock.png to move to the side(+x axis) when my mouse is moving. You can see that _target is the position of the event and the event is the mouse moving.
I then got the node image and set it to a variable.
In the else statement I made the rock.position the position of the _target and gave it somee space away from the _target
I want this to move because my camera moves and I want it to move with the flow of the camera
``
extends Camera2D
const zone = 10
onready var rock = get_node("rocks_png_1")
func _input(event: InputEvent) -> void:
if event is InputEventMouseMotion:
var _target = event.position
if _target.length() < zone:
self.position = Vector2(640,350)
else:
self.position = _target.normalized() * (_target.length() - zone) * 0.5
rock.position = Vector2(int(_target)+40, int(_target)+20)
``
From the code I used above I get this error
Invalid get Index 'position' (on base: 'TextureRact')
I tried just using the same code as I used in my self.position for the camera that made it move, but when I try it for the rock.position it gives me an error that tells me I need a Vector?
Invalid get Index 'position' (on base: 'TextureRact')
The error is telling you that TextureRect does not have a position property.
What happens is that a TextureRect is a Control which are positioned differently from Node2D (Camera2D is a Node2D). You can try using rect_position with it. Although I think you would be better off using a Sprite instead of a TextureRect (Sprite is a Node2D).
Notice that your TextureRect is a child of the Camera2D in the scene tree. Well, a Node2D would move with its parent automatically. So changing it to Sprite would negate the need of the line of code you are using to move it.
… Actually, due to the way Camera2D works (it has drag and limits) you might still want do something (depending what your goal is). So, know that the get_camera_screen_center method will give you the actual visual center of the screen (which is not the target of the Camera2D, again due to drag and limits).

Why isn't my path2d position updating?

I created a new path2d following the instructions in the my first game article: http://docs.godotengine.org/en/3.0/getting_started/step_by_step/your_first_game.html
I wanted to move the "box" on screen so that I could see how the mobs spawn in, but when I ran the scene, it stayed off screen.
I created a new path2d, centered this one in the middle of the screen, and it works like I wanted it to, but now I moving this one in the editor doesn't update the position in game.
What's going on?
Thanks
func _on_mobtimer_timeout():
$mobtimer.wait_time = 0.1 + randf() / 2
$mobspawn/moblocation.set_offset(randi())
var mob = Mob.instance()
add_child(mob)
var direction = $mobspawn/moblocation.rotation + PI/2
mob.position = $mobspawn/moblocation.position
direction += rand_range(-PI/8, PI/8)
mob.rotation = direction
mob.set_linear_velocity(Vector2(rand_range(200, 200 + score * 30), 0).rotated(direction))
A Node2D's position property is relative to it's parent's position. The code from the Dodge The Creeps tutorial assumes that MobPath is located at 0, 0 and fails when that assumption is false.
In your case you are taking a MobSpawnLocation's position relative to MobPath and then setting it as the new Mob's global position.
Luckily Node2D's have another property that we can use in these circumstances global_position. It can be used like this:
mob.position = $mobspawn/moblocation.global_position
http://docs.godotengine.org/en/stable/classes/class_node2d.html#member-variables
This isn't a full solution, but I found a weird workaround. Instead of changing the position in the editor, if you use the nodes on the orange box (at the intersection of orange and blue), you can kind of alternate to move the box around.

Get and set correct window position with node.js

In the close event I persist the window position as follows:
localStorage.lastlayout = JSON.stringify({
"left": win.x,
"top": win.y,
"width": win.width,
"height": win.height
});
On start, I restore it with:
data = JSON.parse(localStorage.lastlayout);
win.moveTo(data.left, data.top);
win.resizeTo(data.width, data.height);
The problem is the position is off. As far as I can tell, I get the inner position. When setting I set the outer position. The windowing title and borders only accounted for when setting.
As this is cross-platform code I cannot test it on all platforms (yet) and I don't know if it is possible to get the metrics of the windowing engine so that I can correct it programmatically (think about the user changing the DPI or theme on Windows).
Is there a way to compensate for this?
Ok, I've nailed it. I detect the offsets in respect to a known position (0, 0) and then detract it from the desired position. It's not perfect but it works:
win.resizeTo(128, 128);
win.moveTo(0, 0);
log("dbg", "win", "detected metrics: " + win.x + ", " + win.y);
win.moveTo(data.left - win.x, data.top - win.y);
win.resizeTo(data.width, data.height);
The initial resize is necessary for some reason. It looks like the title and borders are not drawn at all on some platforms if the window is not large enough. Next I move it to the origin. The win.x and win.y contain the offsets at this point. The second moveTo() uses the corrected coordinates and finally I resize the window to the actually desired size.

AndroidPlot - Labels and text

I am a non-developer product manager for an application built in both Android and iOS. We have a bar graph in iOS that provides text for the content of the graph. It displays Totals for each bar, and percentages for each segment of each bar.
In Android, using AndroidPlot (so I understand) we just display the bars with different color segments and no percent totals or totals. I am told by the developer that we can't show more.
I would display the images here, but stackoverflow tells me I don't have enough reputation points to do this. I have created a link to my dropbox with the images https://www.dropbox.com/sh/2uocm5bn79rerbe/AAB7s9QEEYIRIgXhKbUAaOyDa
Is it possible to use AndroidPlot to emulate this iOS chart or at least represent to same information to the end user?
Your developer is more or less correct but you have options. Androidplot's BarRenderer by default provides only an optional label at the top of each bar, which in your iOS images is occupied by the "available", "new", "used" and "rent" label. That label appears to be unused in your Android screenshot so one option would be to utilize those labels do display your totals.
As far as exactly matching the iOS implementation with Androidplot, the missing piece is the ability to add additional labels horizontally and vertically along the side of each bar. You can extend BarRenderer to do this by overriding it's onRender(...) method. Here's a link for your developer that shows where in the code he'll want to modify onRender(...).
I'd suggest these modifications to add the vertical labels:
Invoke Canvas.save(Canvas.ALL_SAVE_FLAG) to store the default orientation of the Canvas.
Use Canvas.translate(leftX, bottom) to center on the bottom left point of the bar
Rotate the Canvas 90 degrees using Canvas.rotate(90) to enable vertical text drawing
Draw whatever text is needed along the side of the plot; 0,0 now corresponds to the bottom left corner of the bar so start there when invoking canvas.drawText(x,y).
Invoke Canvas.restore() to restore the canvas' original orientation.
After implementing the above, adding horizontal "%" labels should be self evident but if you run into trouble feel free to ask more questions along the way.
UPDATE:
Here's a very basic implementation of the above. First the drawVerticalText method:
/**
*
* #param canvas
* #param paint paint used to draw the text
* #param text the text to be drawn
* #param x x-coord of where the text should be drawn
* #param y y-coord of where the text should be drawn
*/
protected void drawVerticalText(Canvas canvas, Paint paint, String text, float x, float y) {
// record the state of the canvas before the draw:
canvas.save(Canvas.ALL_SAVE_FLAG);
// center the canvas on our drawing coords:
canvas.translate(x, y);
// rotate into the desired "vertical" orientation:
canvas.rotate(-90);
// draw the text; note that we are drawing at 0, 0 and *not* x, y.
canvas.drawText(text, 0, 0, paint);
// restore the canvas state:
canvas.restore();
}
All that's left is to invoke this method where necessary. In your case it should be done once per BarGroup and should maintain a consistent position on the y axis. I added the following code to the STACKED case in BarRenderer.onRender(...), immediately above the break:
// needed some paint to draw with so I'll just create it here for now:
Paint paint = new Paint();
paint.setColor(Color.WHITE);
paint.setTextSize(PixelUtils.spToPix(20));
drawVerticalText(
canvas,
paint,
"test",
barGroup.leftX,
basePositionY - PixelUtils.dpToPix(50)); // offset so the text doesnt intersect with the origin
Here's a screenshot of the result...sorry it's so huge:
Personally, I don't care for the fixed y-position of these vertical labels and would prefer them to float along the upper part of the bars. To accomplish this I modify my invocation of drawVerticalText(...) to look like this:
// needed some paint to draw with so I'll just create it here for now:
Paint paint = new Paint();
paint.setColor(Color.WHITE);
paint.setTextSize(PixelUtils.spToPix(20));
// right-justify the text so it doesnt extend beyond the top of the bar
paint.setTextAlign(Paint.Align.RIGHT);
drawVerticalText(
canvas,
paint,
"test",
barGroup.leftX,
bottom);
Which produces this result:

Efficient way of scaling hundreds of QGraphicItems

I have a zoomable QGraphicsView with scene that contains hundreds (and even thousands) of datapoints. The points are represented by QGraphicsEllipseItems and collected into a QGraphicsItemGroup. When the view is zoomed in to I want datapoints to stay at a constant size (i.e., the distances between neigbouring points increase but the sizes stay the same). Right now I achieve this by running this code every time the user zooms in:
#get all the QGraphicsEllipseItems that make up the QGraphicsItemGroup
children = graphics_item_group.childItems()
for c in children:
#base_size_x and base_size_y are the sizes of the
#untrasformed ellipse (on the scene) when zoom factor is 1
#New width and height are obtained from the original sizes and
#the new zoom factors (h_scale, v_scale)
new_width = base_size_x/h_scale
new_height = base_size_y/v_scale
#The top-left corner of the new rectangle for the item has to be recalculated
#when scaling in order to keep the center at a constant position
#For this, the center of the item has to be stored first
old_center_x = c.rect().center().x()
old_center_y = c.rect().center().y()
#New coordinates of the rectangle top left point are calculated
new_topleft_x = old_center_x - new_width/2.
new_topleft_y = old_center_y - new_height/2.
#Finally a new rectangle is set for the ellipse
c.setRect(new_topleft_x, new_topleft_y, new_width, new_height)
This code works. The problem is that it is quite slow (without the compensatory scaling zooming in/out works very smoothly). I tried turning off antialiasing for the view but it makes things look pretty ugly. Is there anything else that I can do to make the processing/redrawing faster?
In the constructor of the QGraphicsItem:
setFlag(ItemIgnoresTransformations);
When you zoom, the item will remain the same size, and you won't have to manually scale it.

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