On Tuesday, 26 May 2026 at 17:42:57 UTC, Dejan Lekic wrote:
On Tuesday, 26 May 2026 at 16:42:16 UTC, c-smile wrote:
widget tree is DOM tree by any means.
1) Mutability
In many GUI toolkits widget trees are completely immutable
(Flutter is perfect example), while DOM is complete opposite -
it is highly mutable
GTK has exactly the same set of DOM/WOM tree mutating operations
(append,prepend,remove):
```c
GtkWidget *button = gtk_button_new_with_label("Click Me");
gtk_container_add(GTK_CONTAINER(page), button);
```
And JS (and you can that in D):
```js
let button = document.createElement("button","Click Me");
page.append(button);
```
So what does immutability mean for you?
where DOM node is a HEAVY, long-lived object!
One more urban legend, sigh ...
Sciter's DOM element is about `sizeof(void*) * 12 = 96 bytes` on
x64.
While `sizeof(struct _GtkWidget)` is 280–380 bytes per widget.
Here is
[sciter-internals.pptx](http://sciter.com/docs/sciter-internals.pptx) - slides of PowerPoint presentation if you want to know more.
2) Structural purpose
DOM is "the end". It holds everything (styles, layout,
structure). In widget-based world widget-tree is actually
high-level abstraction, while at lower layers you _MUST_ have
element-tree and at the lowest layer the "render-objects".
Quite opposite, it is `struct _GtkWidget` that holds everything
styles, layout, structure.
GTK4’s GtkWidgetPrivate contains (summarized):
* Pointers: parent, layout manager, CSS node, first child, next
sibling, controllers, action groups, tooltip, cursor, etc.
* Geometry: allocation struct (4 ints), baseline, margins, expand
flags
* State flags (bitfields)
* Event delivery flags
* Opacity (double)
* Name pointer
* Tick callback list
* Transform cache
* Snapshot data
* Misc bookkeeping
3) Memory footprint
Creating and destroying DOM nodes is super slow.
Sorry, but that is untrue, real numbers:
* Create 10k DOM nodes : 3–10 ms (Chrome/Firefox)
* Create 10k Win32 HWND : 20–40 ms
"dress to impress" stances...
Check my [Sciter.Notes](https://notes.sciter.com/) application:
There is nothing fancy in its UI... Pure productive application,
I deliberately made it matching e-mail app style for the least
astonishment.
But without Sciter it is quite hard to achieve. You do need to
render HTML (note view), you do need WYSIWYG and Markdown
editing. For Markdown you will need MD->HTML and HTML->MD parsers
and the most mature libs for that are in JS.
For the storage you would need something like NoSQL DB as data
associated with notes and overall DB structure is fluid, etc.
