simulate "cls - clear screen" on TDialog - how to can I do this ?

[paule32]

Hello,
I have a TDialog, and I would like insert Text in it.
Currently I use the draw member to "render" the Text - but I fail.
So: how can I use DrawBuffer, to fill a field of 80x25, and draw this buffer to the TDialog ?

[magiblot]

Hi Jens!

TDialog is a TGroup, so its purpose is to contain other views. Therefore, if you want to draw your own things you should instead create a new class inheriting from TView, insert it into your TDialog, and then implement the draw member method of this new class.

Try it this way and let me know if you succeed or not.

[paule32]

when I use the Code below, I get the attached screen.

TOutputWindowChild::TOutputWindowChild(
    TOutputWindow * parent,
    const TRect& bounds):
    TView(bounds),
    owner(parent) {
    
    options |= ofSelectable;
}
void TOutputWindowChild::draw()
{
    int y = 0, ymax = size.y;
    for (y; y < ymax; ++y) {
        writeChar(0, y, 'o', getColor(14), size.x);  // <-- here, I expect 0xe - yellow on black
    }
}

[paule32]

The pros: I solve my problem with the Code below - I used mapColor to make it work.
The cons: I don't know why:

• I have make it twice: use/override the mapColor,
• I have to use getColor(14);

When I use getColor without mapColor, I get not the final result, I expected (writeChar)

TColorAttr
TOutputWindowChild::mapColorOutsideClass(uchar index)
{
    switch (index)
    {
        case  1: return 0x01; break;
        case  2: return 0x02; break;
        case 14: return 0x0e; break;
        case 15: return 0x0f; break;
        
        default:
            return TView::mapColor(index);
    }
}

void TOutputWindowChild::drawContent()
{
    int y = 0, ymax = size.y;
    for (y; y < ymax; ++y) {
        writeChar(0, y, 'o', getColor(14), size.x);
    }
}

[paule32]

this is now, what I expect:

[magiblot]

I'll explain what happened:

The mapColor and getColor methods are related to the palette system. They both get a palette index and return a color attribute (TColorAttr: the foreground color, background color and style of a cell). The difference is that getColor allows you to retrieve two color attributes at once; that's why it returns an attribute pair (TAttrPair).

Your view TOutputWindowChild is being inserted onto a TDialog. Therefore, when it comes to the palette system, the list of color indices that you can use is that of TDialog:

tvision/include/tvision/dialogs.h

Lines 39 to 75 in f369a73

	/* ---------------------------------------------------------------------- */
	/* class TDialog */
	/* */
	/* Palette layout */
	/* 1 = Frame passive */
	/* 2 = Frame active */
	/* 3 = Frame icon */
	/* 4 = ScrollBar page area */
	/* 5 = ScrollBar controls */
	/* 6 = StaticText */
	/* 7 = Label normal */
	/* 8 = Label selected */
	/* 9 = Label shortcut */
	/* 10 = Button normal */
	/* 11 = Button default */
	/* 12 = Button selected */
	/* 13 = Button disabled */
	/* 14 = Button shortcut */
	/* 15 = Button shadow */
	/* 16 = Cluster normal */
	/* 17 = Cluster selected */
	/* 18 = Cluster shortcut */
	/* 19 = InputLine normal text */
	/* 20 = InputLine selected text */
	/* 21 = InputLine arrows */
	/* 22 = History arrow */
	/* 23 = History sides */
	/* 24 = HistoryWindow scrollbar page area */
	/* 25 = HistoryWindow scrollbar controls */
	/* 26 = ListViewer normal */
	/* 27 = ListViewer focused */
	/* 28 = ListViewer selected */
	/* 29 = ListViewer divider */
	/* 30 = InfoPane */
	/* 31 = Cluster Disabled */
	/* 32 = Reserved */
	/* ---------------------------------------------------------------------- */

However, in your example you are using the TView::writeChar method, which takes a color index and not a color attribute. In the source code of TView::writeChar you can see that it already calls mapColor. Therefore, it is wrong to call this method with the value returned by getColor.

This is an example of proper usage of TView::writeChar, using the palette index 1:

tvision/source/tvision/textview.cpp

Line 181 in f369a73

writeChar(0, i, ' ', 1, size.x);

But none of this is actually important for what you are trying to accomplish. You already decided that the color attribute you want is 0x0e (yellow on black). You don't need the palette system at all. Therefore, you should use color attributes directly instead of palette indices.

In order to do this you should use TDrawBuffer, the methods of which take color attributes directly. For example:

TDrawBuffer b;
for (int y = 0; y < size.y; ++y) {
    b.moveChar(0, 'o', 0x0e, size.x);
    writeLine(0, y, size.x, 1, b);
}

This way, you don't have to override nor use mapColor and you can forget about palette indices.