I'm looking for best solution - I'm drawing a hexagonal map (Civilization like :) ) for my browser based game in GWT. Currently I'm drawing it on canvas which basically works.
However - I'm also able to slide map left,right,down and up to see another fragment of the map. In such situation I'm forced to redraw the whole map - which doesn't look too good, and will probaly cause preformance issues when the map gets more complex.
Is there a better approach for that? Some library? Or maybe I should make every hex a button like widget. so I could be able to move it instead creating from the scratch... but what about different resolutions then... I'm affraid the map could tear apart sometimes...
You could try doing it will simple DIVs (FlowPanel, HTMLPanel, etc) and style the hexagons using CSS. See this tutorial: http://jtauber.github.com/articles/css-hexagon.html
There are some neat suggestions here as well: html/css hexagon with image inside and hexagonal shaped cells in html
You could draw the entire map (usually just the relatively static background, not the animations!) in a hidden canvas, and then copy the parts you need to your visible canvas:
final Canvas hiddenCanvas = buildCanvas(1000, 1000);
drawHexPattern(hiddenCanvas);
// don't add the hiddenCanvas to your DOM
final Canvas visibleCanvas = buildCanvas(320, 200);
RootPanel.get().add(visibleCanvas); // add the visibleCanvas to the DOM
showArea(hiddenCanvas, visibleCanvas, 0, 0);
...
showArea(hiddenCanvas, visibleCanvas, 20, 10);
...
With a showArea() method like
private void showArea(final Canvas hiddenCanvas, final Canvas visibleCanvas,
final double x, final double y) {
final Context2d hiddenCtx = hiddenCanvas.getContext2d();
final Context2d visibleCtx = visibleCanvas.getContext2d();
final ImageData imageData = hiddenCtx.getImageData(x, y,
visibleCanvas.getCoordinateSpaceWidth(),
visibleCanvas.getCoordinateSpaceHeight());
visibleCtx.putImageData(imageData, 0, 0);
}
I created a pastebin with a working example: http://pastebin.com/tPN2093a
Related
I'm trying to create a custom scrollable text area. I created a DrawingArea and a ScrollBar inside a Grid. I have attached the draw event of DrawingArea to this.on_draw method which simply looks at ScrollBar's value and moves the Cairo.Context appropriately before drawing the Pango.Layout.
The first problem is that this.on_draw is getting invoked whenever the ScrollBar is touched even though I have not registered any events with ScrollBar. How do I prevent this, or check this?
The second problem is that even though this.on_draw is invoked, the changes made to the Context is not displayed unless the ScrollBar value is near 0 or 100 (100 is the upper value of Adjustment). Why is this happening?
I did find out that if I connect the value_changed event of ScrollBar to a method that calls queue_redraw of DrawingArea, it would invoke this.on_draw and display it properly after it. But due to the second problem, I think this.on_draw is getting invoked too many times unnecessarily. So, what is the "proper" way of accomplishing this?
using Cairo;
using Gdk;
using Gtk;
using Pango;
public class Texter : Gtk.Window {
private Gtk.DrawingArea darea;
private Gtk.Scrollbar scroll;
private string text = "Hello\nWorld!";
public Texter () {
GLib.Object (type: Gtk.WindowType.TOPLEVEL);
Gtk.Grid grid = new Gtk.Grid();
this.add (grid);
var drawing_area = new Gtk.DrawingArea ();
drawing_area.set_size_request (200, 200);
drawing_area.expand = true;
drawing_area.draw.connect (this.on_draw);
grid.attach (drawing_area, 0, 0);
var scrollbar = new Gtk.Scrollbar (Gtk.Orientation.VERTICAL,
new Gtk.Adjustment(0, 0, 100, 0, 0, 1));
grid.attach (scrollbar, 1, 0);
this.darea = drawing_area;
this.scroll = scrollbar;
this.destroy.connect (Gtk.main_quit);
}
private bool on_draw (Gtk.Widget sender, Cairo.Context ctx) {
ctx.set_source_rgb (0.9, 0.9, 0.9);
ctx.paint ();
var y_offset = this.scroll.get_value();
stdout.printf("%f\n", y_offset);
ctx.set_source_rgb (0.25, 0.25, 0.25);
ctx.move_to(0, 100 - y_offset);
var layout = Pango.cairo_create_layout(ctx);
layout.set_font_description(Pango.FontDescription.from_string("Sans 12"));
layout.set_auto_dir(false);
layout.set_text(this.text, this.text.length);
Pango.cairo_show_layout(ctx, layout);
return false;
}
static int main (string[] args) {
Gtk.init (ref args);
var window = new Texter ();
window.show_all ();
Gtk.main ();
return 0;
}
}
Also, please point out any (possibly unrelated) mistake if you find one in the above code.
The part that you are missing is that a draw signal does not mean "redraw everything". Instead, GTK+ sets the clip region of the cairo context to the part that needs to be redrawn, so everything else you do doesn't have any effect. The cairo function cairo_clip_extents() will tell you what that region is. The queue_draw_area() method on GtkWidget will allow you to explicitly mark a certain area for drawing, instead of the entire widget.
But your approach to scrollbars is wrong anyway: you're trying to build the entire infrastructure from scratch! Consider using a GtkScrolledWindow instead. This automatically takes care of all the details of scrolling for you, and will give you the overlay scrollbars I mentioned. All you need to do is set the size of the GtkDrawingArea to the size you want it to be, and GtkScrolledWindow will do the rest. The best way to do this is to subclass GtkDrawingArea and override the get_preferred_height() and/or get_preferred_width() virtual functions (being sure to set both minimum and natural sizes to the sizes you want for that particular dimension). If you ever need to change this size later, call the queue_resize() method of GtkWidget. (You probably could get away with just using set_size_request(), but what I described is the preferred way of doing this.) Doing this also gives you the advantage of not having to worry about transforming your cairo coordinates; GtkScrolledWindow does this for you.
I am trying to use de Image Button on LIBGDX to create a button based on two images.
Using add to second image, works fine, but have one problem.
The images are of different sizes.
Note: I am testing with the same picture to see the result
Is there a way to correct this? Using some scale to the images?
levelsTexture = new Texture(Gdx.files.internal("level1.png"));
levels = new TextureRegion(levelsTexture).split(TILE_WIDTH, TILE_HEIGHT);
ImageButton levels_image = new ImageButton(new TextureRegionDrawable(new
TextureRegion(levels[0][0])));
levels_image.add(new Image (levels[0][0]));
stage.addActor(levels_image);
levels_image.setScale(2f);
The problem:
ImageButton is an extension of the Table class and typically the ImageButton images are set as the background. Using the "add" method for the second image like you did might work kind of, but it behaves differently than setting the background and it also might not be what you want if you want the the second image to also change when you click the button.
The easiest way to add two images to a single ImageButton would be to simply combine the two images in Photoshop (or equivalent) and use that single image on the ImageButton.
The more advanced (and more flexible) method would be to combine the two images programmatically and use this as the background for your ImageButton. This can be done by creating a custom class which extends BaseDrawable and have it take two Images in the constructor. If you want your images stacked on top of each other, set the minHeight of your custom drawable class to be the combined height of your two images. Then override the draw method and draw your two images on top of each other like this:
#Override
public void draw(Batch batch, float x, float y, float width, float height){
img1.getDrawable().draw(batch, x, y, img1.getWidth(), img1.getHeight());
img2.getDrawable().draw(batch, x, y+img1.getHeight(), img2.getWidth(), img2.getHeight());
}
}
The ImageButton takes a Drawable in its constructor, so you can pass this object right into the button when you create it and both of your Images should appear in the button and they will be treated as one.
I've done something similar to make a background for a table using multiple Images and this method works great.
I wrote my own SpriteButton class in which I implement this method for scaling my textures.
private Dimension getScaledDimension(Dimension imgSize, Dimension boundary) {
int original_width = imgSize.width;
int original_height = imgSize.height;
int bound_width = boundary.width;
int bound_height = boundary.height;
int new_width = original_width;
int new_height = original_height;
// first check if we need to scale width
if (original_width > bound_width) {
//scale width to fit
new_width = bound_width;
//scale height to maintain aspect ratio
new_height = (new_width * original_height) / original_width;
}
// then check if we need to scale even with the new height
if (new_height > bound_height) {
//scale height to fit instead
new_height = bound_height;
//scale width to maintain aspect ratio
new_width = (new_height * original_width) / original_height;
}
return new Dimension(new_width, new_height);
}
Then finally you draw the texture with the output dimension as as size to draw.
sb.begin();
sb.draw(this.texture2, this.x, this.y, dim_size_new.width, dim_size_new.height);
sb.end();
So you could technically draw the second image to the size of the the first image, if the first image size is correct.
Your implementation will look different from mine but you should be able to figure it out form here on out.
I'm trying to create a label decorator to add an icon to the top left of my file icons. I see that the little red X can be drawn off of the edge of the icon, but my radiation symbol is cut off at the edge.
l
#Override
public Image decorateImage(Image image, Object element) {
Image failureImg = Activator.imageDescriptorFromPlugin(IMAGE PATH).createImage();
GC gc = new GC(image);
gc.drawImage(failureImg, 0, 0, failureImg.getImageData().width, failureImg.getImageData().height,
0, 0, 11, 11);
gc.dispose();
return image;
}
Any ideas on how to draw outside of the bounds of the file icon?
It is easier to use a lightweight label decorator (implement ILightweightLabelDecorator and specify lightweight="true" in the extension point).
You can then add the decoration image with:
#Override
public void decorate(final Object element, final IDecoration decoration)
{
ImageDescriptor imageDescriptor = Activator.imageDescriptorFromPlugin(IMAGE PATH);
decoration.addOverlay(imageDescriptor, IDecoration.TOP_LEFT);
}
Since lightweight decorators are run in a background thread they also make the UI more responsive.
Note: Your code is creating Image objects and not arranging for them to be disposed - this leaks resource handles. The lightweight decorator does not have this issue.
For the purpose of mine gstreamer application I tought about simple loader before I give a handle of DrawingArea widget to sink element.The basic idea was to load an animated .gif inside Gtk.DrawingArea but I run on the problem with documentation.I found out about PixbufAnimation and I used it with Gtk.Image widget but the same logic doesn't work for Gtk.DrawingArea and since it doesn't have add method I don't know what to do so as my last resort I came here to get a help.
This is what I did with Gtk.Image:
from gi.repository import Gdk,Gtk,GdkPixbuf
class animatedWin(Gtk.Window):
def __init__(self):
Gtk.Window.__init__(self,width_request=640,height_request=480)
self.canvas=Gtk.Image()
self.add(self.canvas)
self.load_file()
self.connect("delete-event",self.Gtk.main_quit)
def load_file(self):
self.loader=GdkPixbuf.PixbufAnimation.new_from_file("loader.gif")
self.canvas.set_from_animation(self.loader)
app=animatedWin()
app.show_all()
Gtk.main()
is it possible to achieve the same thing with DrawingArea ?
DrawingArea like most widgets in gtk3 uses cairo for drawing on them. Cairo draws on surfaces using context. You can convert pixbuf into surface by
public Surface Gdk.cairo_surface_create_from_pixbuf (Pixbuf pixbuf, int scale, Window? for_window)
And back by
public Pixbuf? Gdk.pixbuf_get_from_surface (Surface surface, int src_x, int src_y, int width, int height)
(taken from valadoc.org)
Example code snippet from my drawing app (I'm learning Vala while I writing it, so it may not be best implementation):
private void on_scale (Gtk.Button button) { // on button press
var my_pixbuf = Gdk.pixbuf_get_from_surface (this.buf_surface, 0, 0, CANVAS_WIDTH, CANVAS_HEIGHT);
var tmp_surface = Gdk.cairo_surface_create_from_pixbuf (my_pixbuf, 2, null);
var ctx = this.ccc; //this.ccc is context of drawing surface
ctx.set_source_surface (tmp_surface, 0, 0);
ctx.paint();
drawing_area.queue_draw(); // ask drawing_area to redraw, on redraw I have function/method that will paint drawing_area widget surface with drawing surface
}
PS. see http://valadoc.org/#!api=cairo/Cairo for more info on cairo. As I see it, cairo used for vector graphics and pixbuf for raster.
I want to use the clientBundle capability of GWT to load only 1 image, which is composed of many sprites, with GWTCanvas. My initial take was to just convert the ImageResource into an ImageElement, but apparently that doesn't seem to work:
public interface Bundle implements ClientBundle{
public static Bundle INSTANCE = GWT.create(Bundle .class);
#Source("/img/tile1.png")
public ImageResource tile1()
}
final GWTCanvas canvas = new GWTCanvas(400,400);
canvas.drawImage(ImageElement.as(new Image(Bundle.INSTANCE.tile1()).getElement()), 0, 0);
i tried adding the Image to RootPanel first (to force a load), but that doesn't seem to work too. Perhaps the timings are incorrect. Does anyone have a clue as to how I can draw an imageResource using GWTCanvas?
This works: (GWT 2.4)
// load:
SafeUri uri= imageResource.getSafeUri();
ImageElement imgElement= ImageElement.as((new Image(uri)).getElement());
// render
context.drawImage(imgElement, 0, 0);
You can get the image from a bundle using a data URI, but you'll need to manage the asynchrony as you would with a remote image.
final Image image = new Image(resources.imageResource().getURL());
RootPanel.get().add(image);
image.setVisible(false);
fetchedImage.addLoadHandler(new LoadHandler() {
public void onLoad(LoadEvent event) {
context.drawImage(ImageElement.as(image.getElement()), 0, 0);
}
});
Using ClientBundled image in the way you want isn't possible. Images combined to one big image are displayed as background images which is based on the feature of the browser to show only part of an image. GWT calls this 'clipped' mode. So when you try to get the element of that image, the actual src tag is empty as the image is a background image. If you want to display images on the Canvas it must be an actual link to an image.
You might try using the ImageResource's getURL() method when you create the image:
canvas.drawImage(ImageElement.as(new Image(Bundle.INSTANCE.tile1().getUrl()).getElement(), 0, 0);
I was having the same problem when using a ClientBundle with GWT 2.2.0's Canvas type and this fixed it for me.
They are correct, just use getSafeUri() instead of getURL()
The solution of Tom Fishman didn't work for me, because the images weren't loaded at the time when i called canvas.drawImage(). This solution works (also for big images):
// Create Image
SafeUri uri = resource.getSafeUri();
Utils.console("URI: "+ uri);
final Image img = new Image(uri);
// Add the image to the RootPanel to force the image to be loaded.
RootPanel.get().add(img);
// The image has to be added to the canvas after the image has been loaded.
// Otherwise the bounding box of the image is 0,0,0,0 and nothing will be drawn.
img.addLoadHandler(new LoadHandler() {
#Override
public void onLoad(LoadEvent event) {
// Create the image element.
ImageElement imgElement = ImageElement.as(img.getElement());
// Render the image on the canvas.
context2d.drawImage(imgElement, offsetX, offsetY);
// Delete the image from the root panel.
RootPanel.get().remove(img);
}
});