I have a "tooltip.png" file in my local directory.
the code below works when i put it in int main() but doesn't work when i put it in my MainWindow class constructor:
QGraphicsScene scene;
QGraphicsView *view = new QGraphicsView(&scene);
QGraphicsPixmapItem item(QPixmap("tooltip.png"));
scene.addItem(&item);
view.show();
in int main() it show the picture but in constructor doesn't
You create scene on the stack, meaning that it will be deleted once it goes out of scope, which is at the end of the constructor.
Try constructing scene like this inside the constructor of your MainWindow:
QGraphicsScene scene(this);
By providing a parent to the scene, Qt will make sure it remains alive together with that parent (in your case you mainWindow).
Since Qt takes care of the memory management, you can use pointers without fear of memory leaks:
QGraphicsScene* scene = new QGraphicsScene(this);
QGraphicsView* view = new QGraphicsView(scene, this); // Give the view a parent too to avoid memory leaks
QGraphicsPixmapItem* item = new QGraphicsPixmapItem(QPixmap("tooltip.png"), this);
scene->addItem(&item);
view->show();
Related
This is difficult to explain with typing...
I have a GameController scene (Node2D) that holds 3 instanced scenes within:
Mouse (scenes/Mouse.tscn) - this just swaps the mouse cursor for a custom graphic
HeaderBar (scenes/HeaderBar.tscn) - this is the score/label that just sits up top
Messages (scenes/Messages.tscn) - this is the "popup" message box that displays text to the user
In the main scene (Level1.tscn) I instance the GameController scene and it "works" fine. The header bar is there with the score/label and the custom mouse cursor is there and the message box is there (but I have it hidden by default but if I toggle its visibility in the remote it will show up).
Here's where my confusion comes in...
If I attempt, in the GameController script, to manipulate any of those nodes in the GameController scene (the mouse, header, messages) they return as null and will throw an error. For example; if I try to update the score in the $HeaderBar/Control/score I get the following:
Invalid set index 'text' (on base: 'null instance') with value of type 'String'.
The code completion will autofill the node names as I type them (so it recognizes them in the group) but any attempt to reference/use them in script throws similar errors to above.
I'm very new to Godot so I'm sure it's just some misunderstanding I have on how this type of thing works but I'm stumped! Any insight is much appreciated!
UPDATE
I will try to simplify my explanation a bit (I have made some changes). Okay here is the object script:
extends StaticBody2D
onready var main = load("res://scenes/MainGame.gd").new()
func _ready():
pass
# mouse [left] clicked on object
func _on_trigger_input_event(viewport, event, shape_idx):
if Input.is_action_just_pressed("left-click"):
main.display_message("you [left] clicked on the object!")
the call to main.display_message() works. It does call the function but here is that function in the MainGame.gd
extends Node2D
onready var box = $Message/Control
onready var label = $Message/Control/Label
func _ready():
# hide the mouse cursor (will use custom cursor)
Input.set_mouse_mode(Input.MOUSE_MODE_HIDDEN)
func display_message(msg):
label.text = msg
box.visible = true
It errors out because label (and box) are null. If I call display_message from the _ready function (in the MainGame.gd) it works as it should. Call it from outside (in the Object.gd) and the nodes are null for some reason.
This instances the scene as expected:
onready var main = load("res://scenes/MainGame.gd").new()
However, this code will run when the instanced scene is added to the scene tree:
onready var box = $Message/Control
onready var label = $Message/Control/Label
func _ready():
# hide the mouse cursor (will use custom cursor)
Input.set_mouse_mode(Input.MOUSE_MODE_HIDDEN)
Yes, both onready variables and _ready will run when this is added to the scene tree.
And when do you add main to the scene tree? I don't see where.
Then when you do this:
main.display_message("you [left] clicked on the object!")
Both box and label will still be null (which is the default value).
Thus, add it to the scene tree, for example:
func _ready():
add_child(main)
Except that does not work either, does it? Look at the code again:
onready var main = load("res://scenes/MainGame.gd").new()
You are instancing a script. A script. Not a scene. It will not have its children nodes and so on. You want to instance a scene, for example:
onready var main = load("res://scenes/MainGame.tscn").instance()
However, I find it odd that you are doing this in a StaticBody2D. I don't think it makes sense that MainGame belongs to a StaticBody2D.
I suspect, you are instancing MainGame in multiple places expecting it be the same instance. But it is not the same instance, it is a new instance.
Here is where I suggest you make MainGame into a autoload, so there is a single instance that you can access from anywhere. However, perhaps that is not right either. Perhaps you should use a Signal Bus. See Why does this variable keep returning to its original value? which had a similar problem (they where trying to open a door, you are trying to show a message, but still).
I’m working in C on a project to capture data from a sensor and display it as part of a GUI application on the Raspberry Pi. I am using GTK 3.0, plus Cairo for graphing. I have built an application that works, but I want to make a modification to enable me to change the frequency of data capture.
Within my main code section I have a command like:-
gdk_threads_add_timeout (250, data_capture, widgets);
This all works, the data capture routine is triggered every 250mS, but I want to add functionality to the GUI to enable the user to change the speed. If I try to call this function from anywhere else other than main, it fails.
I have looked for other ways to do it, but I can’t find any examples or explanations of how I can do it.
Ideally what I would like is something like:-
void update_speed(button, widgets)
// Button to change speed has been pressed
read speed from GUI
update frequency
return
int main()
...
setup GUI
set default speed
start main GTK loop
Does anyone have any idea how I could achieve this?
Edit: Additional Code Snippet
(This is not the whole program, but an extract of main)
int main(int argc, char** argv) {
GtkBuilder *builder;
GtkWidget *window;
GError *err = NULL; // holds any error that occurs within GTK
// instantiate structure, allocating memory for it
struct app_widgets *widgets = g_slice_new(struct app_widgets);
// initialise GTK library and pass it in command line parameters
gtk_init(&argc, &argv);
// build the gui
builder = gtk_builder_new();
gtk_builder_add_from_file (builder, "../Visual/gui/main_window.glade", &err);
window = GTK_WIDGET(gtk_builder_get_object(builder, "main_application_window"));
// build the structure of widget pointers
widgets->w_spn_dataspeed = GTK_SPIN_BUTTON(gtk_builder_get_object(builder, "spn_dataspeed"));
widgets->w_spn_refreshspeed = GTK_SPIN_BUTTON(gtk_builder_get_object(builder, "spn_refreshspeed"));
widgets->w_adj_dataspeed = GTK_ADJUSTMENT(gtk_builder_get_object(builder, "adj_dataspeed"));
widgets->w_adj_refreshspeed = GTK_ADJUSTMENT(gtk_builder_get_object(builder, "adj_refreshspeed"));
// connect the widgets to the signal handler
gtk_builder_connect_signals(builder, widgets); // note: second parameter points to widgets
g_object_unref(builder);
// Set a timeout running to refresh the screen
gdk_threads_add_timeout(SCREEN_REFRESH_TIMER, (GSourceFunc)screen_timer_exe, (gpointer)widgets);
gdk_threads_add_timeout(DATA_REFRESH_TIMER, (GSourceFunc)data_timer_exe, (gpointer)widgets);
gtk_widget_show(window);
gtk_main();
// free up memory used by widget structure, probably not necessary as OS will
// reclaim memory from application after it exits
g_slice_free(struct app_widgets, widgets);
return (EXIT_SUCCESS);
When I was creating my first tiled map creator in libGDX, I noticed a very strange bug. I creating grid of objects like this:
private static final int GRID_WIDTH=2400;
private static final int GRID_HEIGHT=2400;
private static final int CELL_SIZE=60;
so you can see there are 2400/60x2400/60 objects or cells. I am creating my map like this:
private void createMap(){
cells = new Cell[GRID_WIDTH/CELL_SIZE][GRID_HEIGHT/CELL_SIZE];
for(int i=0;i<GRID_WIDTH/CELL_SIZE;++i){
for(int j=0;j<GRID_HEIGHT/CELL_SIZE;++j){
cells[i][j]=new Cell(textures[0],i*CELL_SIZE,j*CELL_SIZE);
}
}
}
I also have coordinates for my debug in the screen so I know where they started to disappear. Y coordinate is ok there are from 0 to 2400, but on the X they started to disappear at 1500. When I start to draw there some texture every column will be visible to that texture for example (when I start to write texture at x=2100 every disappeared column will be visible to 2100) and when I will delete that texture every column will disappear again to 1500. So the objects are there but they are not visible. It is so annoying does anyone know about this bug?
As you can see coordinates are at the bottom left this is at the beginning:
and this is when I will add there some texture
[Edited] Code with camera:
private float x=GRID_WIDTH/2,y=GRID_HEIGHT/2;
#Override
public void render(float delta) {
batch = new SpriteBatch();
camera=new OrthographicCamera(CAM_WIDTH,CAM_HEIGHT);
viewPos = new Vector3();
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
viewPos.set(Gdx.input.getX(), Gdx.input.getY(), 0);
camera.unproject(viewPos);
batch.begin();
if(Gdx.input.isKeyPressed(Input.Keys.RIGHT) || Gdx.input.isKeyPressed(Input.Keys.D))
x+=SPEED*Gdx.graphics.getDeltaTime();
if(Gdx.input.isKeyPressed(Input.Keys.LEFT) || Gdx.input.isKeyPressed(Input.Keys.A))
x-=SPEED*Gdx.graphics.getDeltaTime();
if(Gdx.input.isKeyPressed(Input.Keys.UP) || Gdx.input.isKeyPressed(Input.Keys.W))
y+=SPEED*Gdx.graphics.getDeltaTime();
if(Gdx.input.isKeyPressed(Input.Keys.DOWN) || Gdx.input.isKeyPressed(Input.Keys.S))
y-=SPEED*Gdx.graphics.getDeltaTime();
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
camera.position.set(x,y,0);
camera.update();
batch.setProjectionMatrix(camera.combined);
batch.end();
}
The camera is correct. The problem is the batch.begin() and batch.end(). As you might know you cannot do batch.begin() and then shaperenderer.begin() directly after each others without closing one of them. Reason for this I am not 100% about. stage works similar. This means we have to close the batch before drawing the stage
batch.end();
stage.draw();
batch.begin();
// draw your batch stuff here
Also it's terrible to do this
batch = new SpriteBatch();
camera=new OrthographicCamera(CAM_WIDTH,CAM_HEIGHT);
inside the render method. Instead, put it into the create() method or some of your own initialize method. The important thing is to not create a new SpriteBatch every frame as the batch isn't collected by the GC. So you have to manually dispose it using batch.dispose() or it will leak so much memory your RAM will be gone in no time.
I hope this helped you out, good luck.
I am developing MFC based SDI application using CFormView class in VC++. My problem is that I need to load image when the dialog initially appears. How to place image in an SDI application..I know for dialog based applications it can be done using OnInitDialog application.But for SDI application there is no such function. I tried placing the image using OnInitialUpdate() and OnPaint() function. But it failed..What should I do to place the image to dialog when it first appears? Please Help
Thanks in advance
Code as I placed in OnInitialUpdate()
void CECUSimulatorView::OnInitialUpdate()
{
CFormView::OnInitialUpdate();
GetParentFrame()->RecalcLayout();
ResizeParentToFit();
hBitmap = LoadImage(0,_T("F:/ECUSimulator/ECUSimulator_New/res/LedOff.bmp"), IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
ImageLoading();
}
Code for the function ImageLoading()
void CECUSimulatorView::OnInitialUpdate()
{
HDC hDC, hDCToDisplay = NULL;
hDC = CreateCompatibleDC(hDCToDisplay);
SelectObject(hDC,hBitmap);
hDCToDisplay = ::GetDC(m_picture.m_hWnd);
m_picture.GetWindowRect(&picRect);
BitBlt(hDCToDisplay,0 , 0, (picRect.right - picRect.left), (picRect.bottom -picRect.top), hDC, 0 ,0 ,SRCCOPY);
DeleteDC(hDC);
DeleteDC(hDCToDisplay);
}
Here
HANDLE hBitmap;
CStatic m_picture; //Picture Control
CRect picRect; //Picture Control Rect
I removed the code from OnInitialUpdate() and placed it in OnPaint() function as follows:
void CECUSimulatorView::OnPaint()
{
CPaintDC dc(this); // device context for painting
hBitmap = LoadImage(0,_T("F:/ECUSimulator/ECUSimulator_New/res/LedOff.bmp"), IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
ImageLoading();
}
Calling LoadImage() in OnInitialUpdate() is ok, the actual painting needs to be done in one of the two following ways:
a) in CECUSimulatorView::OnDraw() -- easier, but may introduce flickering
b) override the OnPaint() function of the m_picture control using ClassWizard and draw the picture there
[the comments in the previous answer was getting very extended, hence a new answer]
a) derive a new class (say CMyPicture) based on CStatic, change m_picture to this new class
b) in CMyPicture, create a handler for WM_PAINT, this will normally be called CMyPicture::OnPaint()
c) change your ImageLoading() function to take a CDC *pDC as parameter and use this DC to render the image
d)
void CMyStatic::OnPaint(void)
{ CPaintDC dc(this);
ImageLoading(&dc); // or even move the painting logic here
}
NOTE: you can load the image in OnInitialUpdate(), no need to load it each time you are painting
An example (for a dialog, but the painting logic should not be affected) in this SO Answer.
I found the answer for my problem.
I used CBitmap class as follows:
CBitmap m_bBitmap1;
In OnInitialUpdate() I wrote as follows :
m_bBitmap1.LoadBitmapW(IDB_BITMAP1);
In OnPaint() I wrote as follows:
m_picture.SetBitmap(m_bBitmap1);
Wherever(In which all functions)need to load image just call the above line of code in corresponding functions..
I have been trying to set the scene's width and height outside of the constructor and it's been to no avail. After looking through the Scene API I saw a method that lets you get the height and width respectively but not one to set the method.. :s (design flaw maybe).
After further research I came across the SceneBuilder and found methods that could modify the height and width. However, I do not know how to apply it to a scene object already created or how to create a SceneBuilder object that could be used in place of the scene object.
Once you created Scene and assigned it to the Stage you can use Stage.setWidth and Stage.setHeight to change both stage and scene sizes simultaneously.
SceneBuilder can't be applied to an already created object, it can only be used for the scene creation.
It seems not possible to set the size of the Scene after it has been created.
Setting the size of the Stage means to set the size of the window, which includes the size of the decoration. So the Scene is smaller in size, unless the Stage is undecorated.
My solution is to compute the size of the decoration while initialization and add it to the size of the Stage when resizing:
private Stage stage;
private double decorationWidth;
private double decorationHeight;
public void start(Stage stage) throws Exception {
this.stage = stage;
final double initialSceneWidth = 720;
final double initialSceneHeight = 640;
final Parent root = createRoot();
final Scene scene = new Scene(root, initialSceneWidth, initialSceneHeight);
this.stage.setScene(scene);
this.stage.show();
this.decorationWidth = initialSceneWidth - scene.getWidth();
this.decorationHeight = initialSceneHeight - scene.getHeight();
}
public void resizeScene(double width, double height) {
this.stage.setWidth(width + this.decorationWidth);
this.stage.setHeight(height + this.decorationHeight);
}
I just wanted to post another answer for those who might have had a similar problem as mine.
http://docs.oracle.com/javase/8/javafx/api/javafx/scene/Scene.html
There is no setWidth() or setHeight(), and the property is ReadOnly, but if you look at
Constructors
Scene(Parent root)
Creates a Scene for a specific root Node.
Scene(Parent root, double width, double height)
Creates a Scene for a specific root Node with a specific size.
Scene(Parent root, double width, double height, boolean depthBuffer)
Constructs a scene consisting of a root, with a dimension of width and height, and specifies whether a depth buffer is created for this scene.
Scene(Parent root, double width, double height, boolean depthBuffer, SceneAntialiasing antiAliasing)
Constructs a scene consisting of a root, with a dimension of width and height, specifies whether a depth buffer is created for this scene and specifies whether scene anti-aliasing is requested.
Scene(Parent root, double width, double height, Paint fill)
Creates a Scene for a specific root Node with a specific size and fill.
Scene(Parent root, Paint fill)
Creates a Scene for a specific root Node with a fill.
As you can see, this is where you can set the height and width if you need to.
For me, I am using SceneBuilder, just as you described you were doing, and needed the width and height of that. I am creating custom controls, so it was weird that it didn't do it automatically, so this is how to do it if you need to.
I could have used setWidth() / setHeight() from the Stage as well.
I had an similar challenge when I wanted to switch between different size scenes in JavaFX.
I did my scene switching by changing the Parent resource of a Scene. The new resource would have larger dimensions than the previous resource so the entire Scene wasn't visible.
Like user2229691's answer stated - my issue turned out to be the Window not matching the Scene's dimensions.
Although I'm not able to comment about decorations - I was able to solve my issue by using:
sceneName.getWindow().sizeToScene();
It works when downsizing and upsizing from my own testing.
Here's some example code so you can better understand what I did:
public void start(Stage stage) throws IOException {
// Height of 300, width of 300
Parent scene1 = FXMLLoader.load(getClass().getResource("scene1.fxml"));
// Height of 400, width of 400
Parent scene2 = FXMLLoader.load(getClass().getResource("scene2.fxml"));
// Starting off in the smaller scene
Scene mainScene = new Scene(scene1); // Scene & Window are 300x300
stage.setScene(mainScene);
stage.show();
// Switching to the larger scene resource, that doesn't fit in the window
mainScene.setRoot(scene2); // Scene is 400x400 but can only see 300x300
// Resizing the window so the larger scene fits
mainScene.getWindow().sizeToScene(); // Window is now 400x400 & everything is visible
}
I hope this helps someone.
Source:
https://docs.oracle.com/javase/8/javafx/api/javafx/stage/Window.html#sizeToScene--