Eppur si muove (2019-06-22)

- Please report bugs with Tk on macOS to the tracker:
	http://core.tcl.tk/tk/reportlist

2. Using Tcl/Tk on macOS
---------------------------

- There are two versions of Tk available on macOS: TkAqua using the native
aqua widgets and look&feel, and TkX11 using the traditional unix X11 widgets.
TkX11 requires an X11 server to be installed, such as Apple's X11 (which is
available as an optional or default install on recent macOS).
TkAqua and TkX11 can be distinguished at runtime via [tk windowingsystem].

- At a minimum, macOS 10.3 is required to run Tcl and TkX11.
TkAqua requires macOS 10.6 or later.

all assume that an autorelease pool is in scope and will be drained
when the event processing cycle ends.

The macOS Tk application does not call the [NSApp run] method at
all.  Instead it uses the event loop built in to Tk.  So the
application must take care to replicate the important features of the
method ourselves.  The way that autorelease pools are handled is
discussed in 5.2 below.  Here we discuss the event handling itself.

The Tcl event loop simply consists of repeated calls to TclDoOneEvent.
Each call to TclDoOneEvent begins by collecting all pending events from
an "event source", converting them to Tcl events and adding them
to the Tcl event queue. For macOS, the event source is the NSApp
object, which maintains an event queue even though its run method
will never be called to process them.  The NSApp provides methods for

5.2 Autorelease pools
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In order to carry out the job of managing autorelease pools, which
would normally be handled by the [NSApp run] method, a private
NSAutoreleasePool* property is added to the TkApplication subclass of
NSApplication. The TkpInit function calls [NSApp _setup] which
initializes this property by creating an NSAutoreleasePool prior to
calling [NSApp finishLaunching].  This mimics the behavior of the
[NSApp run] method, which calls [NSApp finishLaunching] just before
starting the event loop.

Since the CheckProc function gets called for every Tk event, it is an

gets posted by a Tk Application.  To address this, the NSApp object
also implements a semaphore to prevent draining the autorelease pool
in nested calls to CheckProc.

One additional minor caveat for developers is that there are several
steps of the Tk initialization which precede the call to TkpInit.
Notably, the font package is initialized first.  Since there is no
NSAutoreleasePool in scope prior to calling TkpInit, the functions
called in these preliminary stages need to create and drain their own
NSAutoreleasePools whenever they call methods of Appkit objects
(e.g. NSFont).

5.3 Clipping regions and "ghost windows"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Another unusual aspect of the macOS port is its use of clipping
regions.  It was part of Daniel Steffen's original design that the
TkWindowPrivate struct maintains three HIShapeRef regions, named
visRgn, aboveVisRgn and drawRgn.  These regions are used as clipping
masks whenever drawing into an NSView.  The visRgn is the bounding box
of the window with a rectangle removed for each subwindow and for each
sibling window at a higher stacking level.  The drawRgn is the
intersection of the visRgn with the clipping rectangle of the
window. (Normally, the clipping rectangle is the same as the bounding
rectangle, but drawing can be clipped to a smaller rectangle by
calling TkpClipDrawableToRect.) The aboveVisRgn is the intersection of
the window's bounding rectangle with the bounding rectangle of the
parent window.  Much of the code in tkMacOSXSubwindows.c is devoted to
rebuilding these clipping regions whenever something changes in the
layout of the windows.  This turns out to be a tricky thing to do and
it is extremely prone to errors which can be difficult to trace.

It is not entirely clear what the original reason for using these
clipping regions was.  But one benefit is that if they are correctly
maintained then it allows windows to be drawn in any order.  You do

			<direct-parameter description="Script to execute" type="text">
				<type type="text"/>
			</direct-parameter>
			<result description="Result">
				<type type="text"/>
			</result>
		</command>
			<command name="open location" code="GURLGURL"
				 description="Open a URL.">
			<direct-parameter description="URL" type="text">
				<type type="text"/>
			</direct-parameter>
			<result description="Result">
				<type type="text"/>
			</result>
		</command>
	</suite>
</dictionary>

#define NSCursorUpdate NSEventTypeCursorUpdate
#define NSTexturedBackgroundWindowMask NSWindowStyleMaskTexturedBackground
#define NSCompositeCopy NSCompositingOperationCopy
#define NSWarningAlertStyle NSAlertStyleWarning
#define NSInformationalAlertStyle NSAlertStyleInformational
#define NSCriticalAlertStyle NSAlertStyleCritical
#define NSCenterTextAlignment NSTextAlignmentCenter













#define NSAnyEventMask NSEventMaskAny
#define NSApplicationDefinedMask NSEventMaskApplicationDefined

#define NSUtilityWindowMask NSWindowStyleMaskUtilityWindow
#define NSNonactivatingPanelMask NSWindowStyleMaskNonactivatingPanel
#define NSDocModalWindowMask NSWindowStyleMaskDocModalWindow
#define NSHUDWindowMask NSWindowStyleMaskHUDWindow
#define NSTitledWindowMask NSWindowStyleMaskTitled
#define NSClosableWindowMask NSWindowStyleMaskClosable
#define NSResizableWindowMask NSWindowStyleMaskResizable

}

# Evaluate field.

proc ::tsb::eval {id} {
    tailcall $::W call Feval $id
}

# Goto field.

proc ::tsb::goto {{id {}}} {
    if {$id eq ""} {
	tailcall $::W call GotoTop
    }
    tailcall $::W call GotoField $id 0
}

# Print page; on Windows seems not to work, but pressing
# <Control-p> opens the printer dialog at least.

proc ::tsb::print {} {
    tailcall $::W call window.print
}

# A minimal canvas emulation for plotchart. The svg method
# produces SVG into the current (output) field.
#
#  set C [::tsb::canvas ...]
#  $C create line 10 10 20 20 -fill black ...
#  ...
#  $C svg ?viewbox?
#  $C destroy

namespace eval ::tsb {

    variable C
    array set C {cid 0}

	    white-space: -o-pre-wrap;
	    word-wrap: break-word;
	}
	pre, code {
	    font-family: Consolas, Roboto Mono, Liberation Mono, monospace;
	    font-size: 90%;
	}
	img, svg {
	    max-width: 95%;
	}
	.field {
	    border: 1px solid transparent;
	}
	.field:hover {
	    border: 1px dotted #AAAAAA;

	/* The 2nd sin: this drives the Tcl event loop. */
	var Gtimer = window.setInterval(function() {
	    window.external.invoke("0 ::tsb::ping");
	}, 20);

	var Wclear = function(id, later) {
	    /* Type coercion! */
	    if (later == true) {
		needsClear[id] = true;
		return;
	    }
	    if (!needsClear[id]) {
		return;
	    }
	    var output =

		}
	    }
	    needsClear[id] = null;
	};

	var Inhide = function(id, hide) {
	    var input = document.getElementById('in' + id);
	    var outpre = document.getElementById('out' + id + '-pre');
	    var outraw = document.getElementById('out' + id + '-raw');
	    if ((outpre.clientWidth == 0 || outpre.clientHeight == 0) &&
	        (outraw.clientWidth == 0 || outraw.clientHeight == 0)) {
		hide = false;
	    }
	    /* Type coercion! */
	    if (hide == true) {
		input.style.display = 'none';
		outpre.addEventListener('dblclick', function(event) {
		    Inhide(id, 0);
		});
		outraw.addEventListener('dblclick', function(event) {
		    Inhide(id, 0);
		});
	    } else {
		outraw.removeEventListener('dblclick', null);
		outpre.removeEventListener('dblclick', null);
		input.style.display = 'inline';
	    }
	};

	var Winput = function(id, str) {
	    var input = document.getElementById('code' + id);
	    input.value = str;

	    needsClear[id] = true;
	    RunTcl("" + id + " " + input.value);
	};

	var Field = function(id) {
	    var div = document.createElement('div');
	    div.className = 'field';

	    var html = '\n <div class="infield" id="in' + id + '">';
	    html += '\n  <label class="tlabel"';
	    html += ' for="code' + id + '">in(' + id + ')</label>';
	    html += '\n  <textarea class="tin" id="code' + id + '" rows="1"';
	    html += '></textarea>\n </div>';

	    html += '\n <div id="out' + id + '-pre">';
	    html += '<pre></pre></div>';
	    html += '\n <div id="out' + id + '-raw"></div>\n';
	    div.innerHTML = html;
	    document.body.appendChild(div);
	    /* For better readability only. */
	    document.body.appendChild(document.createTextNode('\n'));

	    input.value = str;
	    var lines = str.split(/\r?\n|\r/);
	    var nlines = (lines.length < 50) ? lines.length : 50;
	    input.rows = nlines;
	};

	var GotoTop = function() {
	    var elem = document.getElementById('top');
	    elem.focus();
	    elem.scrollIntoView();
	};

	var GotoField = function(id, isout) {
	    var elem;
	    /* Type coercion! */
	    if (isout == true) {
		elem = document.getElementById('out' + id + '-pre');
	    } else {
		elem = document.getElementById('in' + id);
		if (elem.style.display === 'none') {
		    elem = document.getElementById('out' + id + '-pre');
		}
	    }
	    elem.scrollIntoView();
	};

	var ClearFields = function() {
	    while (1) {
		var fields = document.getElementsByClassName('field');
		if (fields.length > 0) {
		    fields[0].parentNode.removeChild(fields[0]);

	</script>
    }

    # Assemble pieces with empty BODY.
    set D $D_head
    append D $D_style $D_script \
	{</head><body><div id="top" tabindex="0"></div></body></html>}

    # The URL to be displayed.
    # Windows:   data:text/html,<html><head><script>window.external.invoke("0 ::tsb::reload");</script></head></html>
    # MacOS:     data:text/html,<html><head><script>window.external.invoke("0 ::tsb::reload");</script></head></html>
    # WebkitGtk: data:text/html,<html><head><script>window.webkit.messageHandlers.extern.postMessage("0 ::tsb::reload");</script></head></html>

    variable U

}

# Initialize webview; document is loaded indirectly via the URL
# which triggers ::tsb::reload which does the rest, but see
# the ::tsb::ready block below.

set W [::twv::new -width 800 -height 600 -title $::tsb::title \
	   -url $::tsb::U -resizable 1 -debug 1 \
	   -callback ::tsb::call_from_js]

# On Windows this seems the way to load, maybe timing?

if {($tcl_platform(platform) eq "windows") && !$::tsb::ready} {
    after cancel ::tsb::reload0
    ::tsb::reload0