I am trying to draw a GtkLayout using cairo. The layout is huge and I need to get the part that is visible in the container window and update that part only. With GTK2 the expose event data was sufficient to do this. I am not successful with GTK3.
In the function to handle "draw" events, I did the following:
GdkWindow *gdkwin; // window to draw
cairo_region_t *cregion; // update regions
cairo_rectangle_int_t crect; // enclosing rectangle
gdkwin = gtk_layout_get_bin_window(GTK_LAYOUT(layout));
cregion = gdk_window_get_update_area(gdkwin);
cairo_region_get_extents(cregion,&crect);
expy1 = crect.y; // top of update area
expy2 = expy1 + crect.height; // bottom of update area
The problem is that cregion has garbage. Either gdk_window_get_update_area() is buggy or I am not using the right drawing window.
Passing the GtkLayout as follows also does not work (this is the function arg for g_signal_connect):
void draw_function(GtkWidget *layout, cairo_t *cr, void *userdata)
Whatever gets passed is not the GtkLayout from g_signal_connect, but something else.
================= UPDATE ====================
I found a way to do what I want without using GtkLayout.
I am using a GtkDrawingArea inside a viewport.
I can scroll to any window within the large graphic layout
and update that window only. Works well once I figured out
the cryptic docs.
scrwing = gtk_scrolled_window_new(0,0);
gtk_container_add(GTK_CONTAINER(vboxx),scrwing);
drwing = gtk_drawing_area_new();
gtk_scrolled_window_add_with_viewport(GTK_SCROLLED_WINDOW(scrwing),drwing);
gtk_scrolled_window_set_policy(SCROLLWIN(scrwing),ALWAYS,ALWAYS);
scrollbar = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scrwing));
Related
I am creating a app for both android and ios using xamarin and mvvmcross.
In the ios app I want to add outer vertical stackview having nested horizontal stackviews. Basically I just want to create a basic person details screen where will be Label on left and textfield on right which will go in one horizontal stackview and like this there will many horizontal stackviews nested in outer vertical stackview.
I am looking for such example on internet but seems most of the examples are in swift but I was hardly able to find some in c#.
Can someone please help.
Thanks,
Santosh
UIStackView leverages the power of Auto Layout and Size Classes to manage a stack of subviews, either horizontally or vertically, which dynamically responds to the orientation and screen size of the iOS device. You can learn about it through this documentation.
In your case, we can construct a vertical stack to place several horizontal stack:
UIStackView verticalStack = new UIStackView();
View.AddSubview(verticalStack);
verticalStack.Axis = UILayoutConstraintAxis.Vertical;
verticalStack.TranslatesAutoresizingMaskIntoConstraints = false;
// Use auto layout to embed this super vertical stack in the View. Also there's no need to set the height constraint, vertical stack will automatically adjust that depending on its content
verticalStack.LeadingAnchor.ConstraintEqualTo(View.LeadingAnchor).Active = true;
verticalStack.TopAnchor.ConstraintEqualTo(TopLayoutGuide.GetBottomAnchor()).Active = true;
verticalStack.TrailingAnchor.ConstraintEqualTo(View.TrailingAnchor).Active = true;
for (int i=0; i<10; i++)
{
// Here try to put some horizontal stack with Label on left and textfield on right in the father stack.
UIStackView horizontalStack = new UIStackView();
horizontalStack.Distribution = UIStackViewDistribution.EqualSpacing;
horizontalStack.Axis = UILayoutConstraintAxis.Horizontal;
// UIStackView should use AddArrangedSubview() to add subviews.
verticalStack.AddArrangedSubview(horizontalStack);
UILabel textLabel = new UILabel();
textLabel.Text = "text";
UITextField textField = new UITextField();
textField.Placeholder = "enter text";
horizontalStack.AddArrangedSubview(textLabel);
horizontalStack.AddArrangedSubview(textField);
}
But if every horizontal stack's subViews are almost the same style and layouts. Why not try to use UITableView? You just need to set the single cell's contents and layouts, then use it in the tableView. Moreover this control is reused and scrollable.
this.canvas = new Canvas(shell, SWT.NO_BACKGROUND);
I'm using a PaintListener:
this.canvas.addPaintListener(new PaintListener() {
#Override
public void paintControl(PaintEvent e) {
// Draw images
synchronized (imageMarks) {
for (ImageMark mark : Whiteboard.this.imageMarks)
{
Image image = Whiteboard.this.getImage(mark.id);
Point position = ScaledPoint.toSWTPoint(Whiteboard.this.getCanvasSize(), mark.getPosition());
Point bounds = mark.getUnscaledBoundaries(Whiteboard.this.getCanvasSize());
e.gc.drawImage(image, 0, 0, image.getBounds().width, image.getBounds().height, position.x, position.y,
bounds.x, bounds.y);
}
}
// Draw pencil marks
synchronized (pencilMarks) {
e.gc.setLineWidth(LINE_WIDTH);
for (double[] line : Whiteboard.this.pencilMarks)
{
Point lastPosPoint = ScaledPoint.toSWTPoint(Whiteboard.this.getCanvasSize(), new ScaledPoint(line[0], line[2]));
Point newPosPoint = ScaledPoint.toSWTPoint(Whiteboard.this.getCanvasSize(), new ScaledPoint(line[1], line[3]));
e.gc.drawLine(lastPosPoint.x, lastPosPoint.y, newPosPoint.x, newPosPoint.y);
}
}
// Draw pointer, assuming it's there
if (pointerMark != null)
{
synchronized (pointerMark) {
Point pos = ScaledPoint.toSWTPoint(Whiteboard.this.getCanvasSize(), pointerMark.getPosition());
if (pointerMark.isFlipped())
e.gc.drawImage(Whiteboard.pointerImageFlipped, pos.x, pos.y);
else
e.gc.drawImage(Whiteboard.pointerImage, pos.x, pos.y);
}
}
}
});
and redrawing the canvas via a canvas.redraw() call. On 64-bit Linux, this seems to be working without any issues, but strangely enough, on 64-bit Windows, nothing ever ends up being erased or redrawn. For example, if the screen is resized, the pencil markings do not resize as well, they just end up being cut out of the screen. When new marks are added (in other words, when the paint listener is called again), the repositioned markings are redrawn on top of the old ones which didn't scale with the window. In other words, I believe the canvas is not being cleared upon canvas.redraw(). Is there a workaround for this?
You are specifying SWT.NO_BACKGROUND which stops the Canvas being cleared before each paint.
If you use SWT.NO_BACKGROUND it is your paint method's responsibility to draw every pixel of the Canvas.
SWT.NO_BACKGROUND JavaDoc:
By default, before a widget paints, the client area is filled with the
current background. When this style is specified, the background is
not filled, and the application is responsible for filling every pixel
of the client area. This style might be used as an alternative to
"double-buffering" in order to reduce flicker. This style does not
mean "transparent" - widgets that are obscured will not draw through.
MFC doc/view architecture, sdi (more precisely multiple top-level windows).
In my view class, I set my "playground" (i.e. logical space) with SetScrollSizes(); Then I want to limit maximum frame window size to that of view's maximum size.
Here is what I'm doing but I think there might be better solution, please advice:
I'm implementing OnGetMinMaxInfo() in my CMainFrame. There I try to get active view's scroll sizes, and set lpMMI->ptMaxTrackSize appropriately. Below is the code:
void CMainFrame::OnGetMinMaxInfo(MINMAXINFO* lpMMI)
{
// Call base version:
CFrameWndEx::OnGetMinMaxInfo(lpMMI);
// Get active view:
CScrollView *pScrollView = (CScrollView *)GetActiveView();
if (pScrollView && pScrollView->IsKindOf(RUNTIME_CLASS(CMyFckinView)))
{
// Get total size of playground:
CSize sizePlayground = pScrollView->GetTotalSize();
// Test if the size is non-zero, i.e. there is at least one node displayed:
if (sizePlayground.cx && sizePlayground.cy/* && !IsPrintPreview()*/)
{
// Set maximum window size to match our playground size:
CRect rectClient, rectWindow;
pScrollView->GetClientRect(&rectClient);
this->GetWindowRect(&rectWindow);
if (rectWindow.top > -5000 && rectWindow.left > -5000) // Avoid when minimized...
{
lpMMI->ptMaxTrackSize.x = sizePlayground.cx + (rectWindow.Width() - rectClient.Width());
lpMMI->ptMaxTrackSize.y = sizePlayground.cy + (rectWindow.Height() - rectClient.Height());
return;
}
}
}
}
This works but has one problem: When print preview is displayed (standard MFC print preview), I obviously want to allow free window resizing, so I use runtime info GetActiveView()->IsKindOf(...) to determine that active view is really my view, and not print-preview's view (which is CPreviewViewEx). But when I close the print preview, OnGetMinMaxInfo is not called, so I'm unable to adjust frame size according to my view again. As soon as I move the window OnGetMinMaxInfo gets called again and correctly adjusts frame size, but without manually moving the window old size (to which the print preview was sized to) is retained and has ugly artifact.
What can I do? Basically if I could trap the moment when print preview is closed, I could use following trick:
// Trigger the WM_MINMAXINFO message:
CFrameWnd *pFrame = GetParentFrame();
RECT rectWindow;
pFrame->GetWindowRect(&rectWindow);
pFrame->MoveWindow(&rectWindow);
But I don't know how to trap print-preview closure.
What I'm trying to accomplish seems quite standard: who would want to have frame window resized bigger than view's logical size (set by SetScrollSizes())? So there should be some more natural solution maybe?
In your CMyFckinView, handle a message that is reliably sent when the print preview is closed and then post a user message to the mainframe which will trigger your "force minmax" code. Perhaps WM_FOCUS or WM_ACTIVATE?
the problem I am having it that if inside the UIView Draw override, I change the view frame size, drawing a rectangle is not working as expected.
If I change the view frame size outside of the Draw override, it works fine. Is this an expected behavior or is it a problem with monotouch only?
This is the code I am using:
class ChildView : UIView
{
public override void Draw (RectangleF rect)
{
base.Draw (rect);
CGContext g = UIGraphics.GetCurrentContext();
//adding 30 points to view height
RectangleF rec = new RectangleF(this.Frame.Location,this.Frame.Size);
rec.Height+=30;
RectangleF rec_bounds = new RectangleF(0,0,rec.Width,rec.Height);
this.Frame=rec;
this.Bounds=rec_bounds;
//drawing a red rectangle to the first half of view height
UIColor.Red.SetFill();
RectangleF _rect = new RectangleF(this.Bounds.Location,this.Bounds.Size);
_rect.Height=_rect.Height/2;
g.FillRect(_rect);
}
}
However, the output of this code is this: (it should draw only 30 points red, but it draws 60 points)
Here is a link to download the project to reproduce this issue:
www.grbytes.com\downloads\RectangleDrawProblem.rar
Καλημέρα!
This behavior is expected. If you want to change the view's frame inside the Draw override, do it before getting the current context. That is because the graphics context also has a size and that is the size of the view at the time you are retrieving it.
Also, there is no need to set both the Bounds and the Frame of the view. You can just set either of them in this case.
By the way, I don't think you need to call base.Draw(). According to the Apple documentation, "If you subclass UIView directly, your implementation of this method does not need to call super."
I have a view with 4 text boxes and and a logo at the top - when the user is entering information the text pad covers up some of these controls, how can I make the view scroll so that this isn't an issue.
I have tried adding the view to a UIScrollView but that doesn't seem to do anything?
I've included a snippit below of how I've handled your situation. If I'm understanding you correctly, you do not wish to have a scrollable view, rather you want to the view to move in conjunction with switching to and from fields to alleviate and visual hindrances caused by the keyboard.
Goodluck!
private void ScrollTheView(bool movedUp, float scrollamount, UIView ViewToMove)
{
//To invoke a views built-in animation behaviour,
//you create an animation block and
//set the duration of the move...
//Set the display scroll animation and duration...
UIView.BeginAnimations(string.Empty, System.IntPtr.Zero);
UIView.SetAnimationDuration(0.15);
//Get Display size...
RectangleF frame = ViewToMove.Frame;
if (movedUp) {
//If the view should be moved up,
//subtract the keyboard height from the display...
frame.Y -= scrollamount;
}
else {
//If the view shouldn't be moved up, restore it
//by adding the keyboard height back to the original...
frame.Y += scrollamount;
}
//Assign the new frame to the view...
ViewToMove.Frame = frame;
//Tell the view that your all done with setting
//the animation parameters, and it should
//start the animation...
UIView.CommitAnimations();
}
You need to set more to the UIScrollView than just put subviews in it. Set up the ContentSize property properly for the complete size of the subviews so the scrollview knows about the larger content in it, than you can control the scrolling position, zoom factor and so on.
There are plenty of samples on iOS SDK, just check the UIScrollView documentation, transformation to Monotouch from ObjectiveC is straightforward or check blog post at http://blog.touch4apps.com/home/iphone-monotouch-development/monotouch-infinite-loop-image-scroll-view where I have a sample with images autoscrolled in UIScrollView.
something like this.
textBox.EditingDidBegin += delegate {
var offset = scrollView.contentOffset;
offset.Y -= 200;
scrollView.contentOffset = offset;
}