I'm making paint program and when I want to scale the canvas ("zoom" it) I take this:
How can i solve the problem?
Java: 1.8.0_191
The best way to get rid of this is to not use the canvas. I just don't understand why everybody wants to use the canvas. Why don't you use the scene graph? With the scene graph everything is vector based and can be scaled as much as you like. The canvas basically is just an image and if you scale up an image you get what you see.
Related
I am trying to implement a tool into my application. the tool would allow the user to plot a triangle meshes using the mouse. I have looked everywhere for a way to do this, tutorials, examples, etc and have not been successful. I have seen the FXyz library but that does not really simulate What I am trying to accomplish. The goal of the program looks as follows:
Use Case Sequence:
The user adds a png image to the 3D scene or drags it into the 3D scene using the mouse.
Once the image is being displayed the user would then be able to plot a mesh around the image.
Once the user has finished plotting the mesh. There would have to be a way to add the image being overlayed by the mesh as a texture to the mesh. The image should look the same after being added as a texture. Is this too hard or beyond the scope of what can be achieve in JavaFX?
Theoretically It would then be possible to drag the vertices of the mesh at draggable points and successfully applying transformations to the texture. Would this be possible?
Images showing what I am trying to achieve
As you can see maybe after plotting the mesh the points connecting the vertices can be dragged in order to manipulate or transform the shape of the mesh. If the mesh has a texture over it. would the image then also transform ?
Would this be possible with the TriangleMesh class that JavaFX has which by the way there is very little out there which explains how to use it and how the points, face points and texture points work. Very confusing =(.
Target End Result
My question is would the type of manipulation shown in the image above be possible in JavaFX? Can this sort of functionality be achieved using the TriangleMesh class or other similar class in JavaFX ? As you can see what I am trying to achieve is really image manipulation I would appreciate knowing if there is another better way to do this.
I unfortunately do not have any code I can share. I just cant seem to produce any regarding this task. I am not asking to be given code or for someone to solve the problem for me. I just want to see examples be guided into the right direction on how to do this and to know if it is even possible or should I just give up on it!
If you have read this far Thank you so much for your time I really appreciate it.
I have read your question till the end :-) In contrast to many people here you are at least providing a clear description of what you want to achieve. According to my own experience I would say that what you want to do is easily possible with JavaFX and the MeshView is the way to go here.
You can use your image as the texture for this mesh and you can distort the image by manipulating the vertices of this mesh. I have implemented part of your functionality myself for a project so I know that it works.
I use QPainter and the function drawImage to draw an airplane on a map. The image and redrawn each time the position of the airplane changes. The problem is, after some time, the image becomes extremely pixelated. I have tried to use a high quality .svg and that did not help either.
Below is my code. Can somebody spot where the error is or what has caused the image to be so pixelated?
// Load .svg image
airplane->load("AirplaneTopDown.svg");
// Downsize image
airplaneSmall = airplane->scaled(120, 120,Qt::KeepAspectRatio);
// Rotate image by trans
airplaneSmall = airplaneSmall.transformed(trans);
// Draw image and center at a certain screen position
painter.drawImage(airplaneX-airplaneSmall.width()/2,airplaneY-airplaneSmall.height()/2,airplaneSmall);
Below are the images of the drawn airplanes. One taken as screenshot at the beginning of the program runtime another one taken after a couple of minutes.
Airplane
Airplane-pixelated
One of your problems is that you first rescale the image and then rotate it.
The rotation needs to interpolate new pixels from the old ones. The higher the resolution of the input, the better the quality of the interpolation. The quality of your SVG is completely lost after the rescale operation.
The second problem you are facing is that you use the "fast" (default) transformation method. This method does not antialias. So instead of interpolating from several input pixels, it will only take one best fit. Calling transformed() with the second argument Qt::SmoothTransformation and scaled() with the sceond argument Qt::SmoothTransformation |Qt::KeepAspectRatio` will greatly improve your results.
However it is also slower, as is performing the rotation on the image in its original, higher resolution.
The arguably best solution to your problem is to take on a different approach. Instead of loading the SVG into a QImage, which is a raster-based image, you should work with the vector graphics. So the SVG is rendered in the right orientation and scale in the first place. A good starting point is the SVG Viewer Example: http://doc.qt.io/qt-5/qtsvg-svgviewer-example.html
I am making an app using Qt (currently 4.8) which displays a literal map from a large number of QGraphicsScene items. I would like to annotate the view with a scale. My requirement for the scale is that it is permanently fixed w.r.t the viewport widget. It needs to be updated whenever the view scale changes (zoom in, etc). There are other possible overlay items as well (compass, etc) so I'd prefer a generic solution.
I have looked at earlier questions around this which suggest:
using the ItemIgnoresTransform
using an overlay pixmap.
I tried IgnoresTransform but that way didn't work right: I couldn't figure out how to fix it in place in (say) the bottom corner of the viewport and was having some difficulty getting the text and lines always displaying in the correct size.
I scrapped that and subclassed QGraphicsView, adding an overlay pixmap by reimplementing the paintEvent (calls original one, then paints the overlay pixmap on top), and an alignment option to indicate where it goes. Coding some pixmap paint code produces a usable scale on the view. Yay! ... but it doesn't work with scrolls - I get "shattered" renderings of the scale all over, or sometimes no scale at all. I think this is because QGraphicsView::scrollViewportBy() uses viewport()->scroll() so I wondered if switching to ViewportSmartUpdate would help, but it doesn't help enough. I'd prefer not to switch to ViewportFullUpdate as that would likely slow the app down too much (there are millions of items in the scene and that would require a full repaint just to move around).
So. Any ideas from here? Would adapting my pixmap code to write to a new mostly-transparent Widget that is overlaid on the viewport be a better way?
Thanks for any help...
Though it may not be the best way of doing this, in the past I've added custom widgets to the window that holds the QGraphicsView / QGraphicsScene, which have the same graphic style as the QGraphicObjects in the scene. When the view is then used to move objects in the scene, or the scene itself, the items on the window remain in the same place.
Hope that helps.
I would like to add a sphere with a 2d gradient as texture to create a skydome. I read that in openGL this is often solved by rendering the skybox without depthtest in an additonal pass.
I disabled depthTest on my sphere so everything else is drawn in front of it, it's kinda giving me the disired effect but depending on the camera angle it clips through other objects in my scene.
I was looking at several examples which make use of THREE.EffectComposer and a second scene, I may be completely after the wrong thing here but I think that could solve this. The thing is I havent ever touched the effectComposer and have no idea at all how to work with it and which things i exactly need.
I would aprreciate any input on this, maybe I'm after the wrong stuff at all.
Here are two three.js examples in which a skydome with a gradient is created. They do not involve EffectComposer or disabling depth test.
http://mrdoob.github.com/three.js/examples/webgl_lights_hemisphere.html
http://mrdoob.github.com/three.js/examples/webgl_materials_lightmap.html
three.js r.55
You dont have to use a cone or other 3D-geometry to simulate a gradient sky.
I solved it using a canvas (with 3 gradient-spots, lightblue -> white (horizon) -> darkblue) and draw it as sprite in front of my camera with the right distance to it (fog-distance).
You only have to manage the distance when moving/rotating your cam.
Tip: Use mesh.scale.set (xx,xx,1) to zoom the canvas-texture to needed size.
I'm currently working on a WYSISYG editor that allows the user to move, resize and rotate shapes by directly manipulating them. The resizing seems to be fairly complex when the shape is rotated. I got this working for non-rotated shapes, but it will take some trigonometric calculations to resize shapes that are rotated. The registration point is always is the middle of the rectangle because this makes rotating a lot easier.
Before I start implementing this, I was wondering if anyone knew of any libraries or sample source code that does this, or could share some tips and tricks to calculate the transformations.
I have the following parameters:
rotation (in degrees)
width, height
x, y
mouseX, mouseY
I attached a screenshot of what I'm trying to accomplish and another one that has some lines drawn onto it that should allow me to deduct the trigonometric calculations. The cross is the cursor.
alt text http://www.herrodius.com/images/resize.jpg
alt text http://www.herrodius.com/images/resize_lines.jpg
You might look at flex-object-handles, in particular the more recent version 2.
I recommend Transform Manager - http://www.greensock.com/transformmanageras3/
It's actually not that hard. Use the mouse coordinates (mouseX / mouseY)from the rotated display object and they will be transformed for you!