Ticket #19260: RecursiveViews.cpp

#include <stdio.h>

#include <Application.h>
#include <Window.h>
#include <View.h>
#include <Rect.h>


class TestView final: public BView {
private:
    TestView *fSubViews[4] {};

private:
    void UpdateSubViews()
    {
        float width = Frame().Width();
        float height = Frame().Height();
        
        float d = 4;
        if (width >= 3*d && height >= 3*d) {
            BRect rects[4];

            rects[0].Set(d, d, width/2 - d/2, height/2 - d/2);
            rects[1].Set(width/2 + d/2, d, width - d, height/2 - d/2);
            rects[2].Set(d, height/2 + d/2, width/2 - d/2, height - d);
            rects[3].Set(width/2 + d/2, height/2 + d/2, width - d, height - d);
            
            if (fSubViews[0] == NULL) {
                for (int32 i = 0; i < 4; i++) {
                    fSubViews[i] = new TestView(rects[i], "view");
                    AddChild(fSubViews[i]);
                }
            } else {
                for (int32 i = 0; i < 4; i++) {
                    fSubViews[i]->MoveTo(rects[i].LeftTop());
                    fSubViews[i]->ResizeTo(rects[i].Width(), rects[i].Height());
                }
            }
        } else {
            if (fSubViews[0] != NULL) {
                for (int32 i = 0; i < 4; i++) {
                    RemoveChild(fSubViews[i]);
                    delete fSubViews[i];
                    fSubViews[i] = NULL;
                }
            }
        }
    }
    
public:
    TestView(BRect frame, const char *name, uint32 resizingMode = B_FOLLOW_NONE):
        BView(frame, name, resizingMode, B_WILL_DRAW | B_SUBPIXEL_PRECISE | B_FULL_UPDATE_ON_RESIZE | B_FRAME_EVENTS)
    {
        UpdateSubViews();
    }

    void Draw(BRect dirty) final
    {
        BRect rect = Frame().OffsetToCopy(B_ORIGIN);
        SetLowColor(0xff, 0xff, 0xff);
        SetHighColor(0, 0, 0);
        FillRect(rect, B_SOLID_LOW);
        StrokeRect(rect, B_SOLID_HIGH);
    }

    void FrameResized(float width, float height) final
    {
        UpdateSubViews();
    }

};


int main()
{
    BApplication app("application/x-vnd.Test-App");
    BWindow *wnd = new BWindow(
        BRect(0, 0, 256, 256).OffsetByCopy(64, 64),
        "RecursiveViews",
        B_TITLED_WINDOW_LOOK, B_NORMAL_WINDOW_FEEL,
        B_QUIT_ON_WINDOW_CLOSE | B_ASYNCHRONOUS_CONTROLS
    );
    TestView *view = new TestView(wnd->Frame().OffsetToCopy(B_ORIGIN), "view", B_FOLLOW_ALL);
    wnd->AddChild(view);
    wnd->Show();
    app.Run();
    return 0;
}