Subject:
Re: [nanogui] TrueType not using specified background
From:
Junior ####@####.####
Date:
13 Jun 2008 21:26:28 -0000
Message-Id: <B70311C6384.000004F6ejr@inbox.com>
> -----Original Message-----
> From: ####@####.####
> Sent: Fri, 13 Jun 2008 08:28:49 -0800
> To: ####@####.#### ####@####.####
> Subject: Re: [nanogui] TrueType not using specified background
>
>> -----Original Message-----
>> From: ####@####.####
>> Sent: Thu, 12 Jun 2008 19:54:19 -0600
>> To: ####@####.#### ####@####.####
>> Subject: Re: [nanogui] TrueType not using specified background
>>
>>> Is their some design reason why truetype fonts do not use the
>>> background
>>> color specified in gc?
>> The other bitmap fonts do use it but I'm not sure why not ttf fonts.
>>
>> Sounds like a bug, although interesting nobody has found it... try
>> modifying
>> the src/demo/nanox fontdemo?.c app that draws text around a circle,
>> lets use a non-white background. Thinking about this I'll bet that
>> all TTF drawing occurs without drawing any background...
>>
>>
>>> Is this something the that needs to be done in nano-X devfonts code or
>>> is
>>> it something that I need to build into the freetype library?
>>
>> No, this would be done in the devfont.c code. There are two options:
>> when the background is set to ON, then you can either clear the
>> background with a GdFillRect first, then let the engine draw
>> the glyph foreground bits only, or have the engine draw the glyph
>> foreground and background bits. I suggest using the former; internal
>> builtin fonts are displayed using the latter (its pretty slow drawing
>> each bit, TTF uses a blit unlike builtin fonts)
>>
>> Since TTF allows text to be displayed at an angle, I'm betting that
>> this is why its not implemented. The simple case would be to
>> implement it only for non-angled text only.
>
> Hi Greg,
> I added the lines to GdDrawAreaInternal since it appears that only
> freetype2 uses this function:
>
> if (gr_usebg)
> {
> psd->FillRect(psd, x, y, x + width - 1, y + height - 1,
> gr_background);
> }
>
> This is a start with two problems:
> The first problem here is that the bitmap is not fixed and only where the
> fonts are drawn the background is drawn.
> If I can use FillRect on the entire string length then I can clear the
> area before writing the text.
> This is not easy because the space character (0x20) is not written as a
> blank space, it onlu advances the cursor.
> Is their a way round this?
> The other problem is I'll need to define a total height which would be
> considering all the characters in the string.
> Is their a method already implemented to do this?
Hi Greg,
I think I'm almost their. I haven't determing how efficient this patch is yet but so far it seems the best way to do it.
I've added this to freetype2_drawtext:
freetype2_gettextsize(pfont, text, cc, flags, &fnt_w, &fnt_h, &fnt_b);
if (gr_usebg)
{
psd->FillRect(psd, ax, ay-fnt_b-4, ax+fnt_w, ay+fnt_h-4, gr_background);
}
I'm trying to iron out some issues with TFTOP, TFBOTTOM & TFBASELINE. The above is for BASELINE and I think when it's done I'll have to add some condition statements to take care of the others.
Any comments?
Regards,.
Jr.
> Thanks,
> Jr.
>
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