fonts

fonts

[Geert Uytterhoeven]

I'm trying out different fonts with amifb (based on 2.5.56 from Linus).
  - PEARL8x8: OK
  - SUN12x22: garbage (random characters)
  - ProFont6x11: garbage (each different line is filled with a different
    character)
  - MINI4x6: garbage (each different line is filled with a different
    character)

At first I thought it may be caused by xres and yres not divisible by the
fontsize, so I tried a 800x600 mode with MINI4x6. But the problem stayed the
same, except that only a 640x600 window in the right part of the screen was
used.

Is my planar code in amifb to blane, or have other people seen the same?

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



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Re: fonts

[Geert Uytterhoeven]

On Sat, 11 Jan 2003, Geert Uytterhoeven wrote:
> I'm trying out different fonts with amifb (based on 2.5.56 from Linus).
>   - PEARL8x8: OK
>   - SUN12x22: garbage (random characters)
>   - ProFont6x11: garbage (each different line is filled with a different
>     character)
>   - MINI4x6: garbage (each different line is filled with a different
>     character)
> 
> At first I thought it may be caused by xres and yres not divisible by the
> fontsize, so I tried a 800x600 mode with MINI4x6. But the problem stayed the
> same, except that only a 640x600 window in the right part of the screen was
> used.
> 
> Is my planar code in amifb to blane, or have other people seen the same?

BTW, VGA8x16 also works.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



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Re: fonts

[Antonino Daplas]

On Sun, 2003-01-12 at 03:15, Geert Uytterhoeven wrote:
> 
> I'm trying out different fonts with amifb (based on 2.5.56 from Linus).
>   - PEARL8x8: OK
>   - SUN12x22: garbage (random characters)
>   - ProFont6x11: garbage (each different line is filled with a different
>     character)
>   - MINI4x6: garbage (each different line is filled with a different
>     character)
> 
> At first I thought it may be caused by xres and yres not divisible by the
> fontsize, so I tried a 800x600 mode with MINI4x6. But the problem stayed the
> same, except that only a 640x600 window in the right part of the screen was
> used.
> 
> Is my planar code in amifb to blane, or have other people seen the same?
> 

The cfb_imageblit() function exhibited the same behavior.  I think we
both made the wrong assumption that all monochrome bitmaps are packed. I
think the rule is:

    The first pixel on the next scanline is always at the next byte from
    the last pixel of the current scanline.  

So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
last 4 are used as padding.  It's worse with a 4x6 fonts where the
4-bits are just duplicated in the other nibble.

It's a simple fix for imageblit. So here's a patch.

a. Fix for slow_imageblit() so fonts with widths not a multiple of 8
will work.

b. Fixed fast_imageblit() so it always access tables as 32-bit for it to
to work with a 64-bit machine.

James, can you apply?
 
Tony

diff -Naur linux-2.5.54/drivers/video/cfbimgblt.c linux/drivers/video/cfbimgblt.c
--- linux-2.5.54/drivers/video/cfbimgblt.c	2003-01-12 09:48:47.000000000 +0000
+++ linux/drivers/video/cfbimgblt.c	2003-01-12 10:06:59.000000000 +0000
@@ -88,11 +88,13 @@
 
 #if defined (__BIG_ENDIAN)
 #define LEFT_POS(bpp)          (BITS_PER_LONG - bpp)
+#define LEFT_POS32(bpp)        (32 - bpp)
 #define NEXT_POS(pos, bpp)     ((pos) -= (bpp))
 #define SHIFT_HIGH(val, bits)  ((val) >> (bits))
 #define SHIFT_LOW(val, bits)   ((val) << (bits))
 #else
 #define LEFT_POS(bpp)          (0)
+#define LEFT_POS32(bpp)        (0)
 #define NEXT_POS(pos, bpp)     ((pos) += (bpp))
 #define SHIFT_HIGH(val, bits)  ((val) << (bits))
 #define SHIFT_LOW(val, bits)   ((val) >> (bits))
@@ -161,7 +163,7 @@
 				  unsigned long fgcolor, unsigned long bgcolor, 
 				  unsigned long start_index, unsigned long pitch_index)
 {
-	unsigned long i, j, l = 8;
+	unsigned long i, j, l;
 	unsigned long shift, color, bpp = p->var.bits_per_pixel;
 	unsigned long *dst, *dst2, val, pitch = p->fix.line_length;
 	unsigned long null_bits = BITS_PER_LONG - bpp;
@@ -170,10 +172,11 @@
 	dst2 = (unsigned long *) dst1;
 
 	for (i = image->height; i--; ) {
-		shift = 0;
-		val = 0;
+		shift = val = 0;
+		l = 8;
 		j = image->width;
 		dst = (unsigned long *) dst1;
+		s = src;
 
 		/* write leading bits */
 		if (start_index) {
@@ -182,35 +185,33 @@
 			val = FB_READL(dst) & start_mask;
 			shift = start_index;
 		}
+
 		while (j--) {
 			l--;
-			if (*src & (1 << l)) 
-				color = fgcolor;
-			else 
-				color = bgcolor;
+			color = (*s & (1 << l)) ? fgcolor : bgcolor;
 			color <<= LEFT_POS(bpp);
 			val |= SHIFT_HIGH(color, shift);
 			
 			/* Did the bitshift spill bits to the next long? */
 			if (shift >= null_bits) {
 				FB_WRITEL(val, dst++);
-				if (shift == null_bits)
-					val = 0;
-				else
-					val = SHIFT_LOW(color, BITS_PER_LONG - shift);
+				val = (shift == null_bits) ? 
+					0 : SHIFT_LOW(color, BITS_PER_LONG - shift);
 			}
 			shift += bpp;
 			shift &= (BITS_PER_LONG - 1);
-			if (!l) { l = 8; src++; };
+			if (!l) { l = 8; s++; };
 		}
+
 		/* write trailing bits */
  		if (shift) {
 			unsigned long end_mask = SHIFT_HIGH(~0UL, shift);
 
 			FB_WRITEL((FB_READL(dst) & end_mask) | val, dst);
 		}
-		dst1 += pitch;	
 
+		dst1 += pitch;	
+		src += (image->width + 7)/8;
 		if (pitch_index) {
 			dst2 += pitch;
 			dst1 = (char *) dst2;
@@ -224,25 +225,25 @@
 }
 
 static inline void fast_imageblit(struct fb_image *image, struct fb_info *p, u8 *dst1, 
-				  unsigned long fgcolor, unsigned long bgcolor) 
+				  u32 fgcolor, u32 bgcolor) 
 {
 	int i, j, k, l = 8, n;
-	unsigned long bit_mask, end_mask, eorx; 
-	unsigned long fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
-	unsigned long tmp = (1 << bpp) - 1;
-	unsigned long ppw = BITS_PER_LONG/bpp, ppos;
-	unsigned long *dst;
+	u32 bit_mask, end_mask, eorx; 
+	u32 fgx = fgcolor, bgx = bgcolor, pad, bpp = p->var.bits_per_pixel;
+	u32 tmp = (1 << bpp) - 1;
+	u32 ppw = 32/bpp, ppos;
+	u32 *dst;
 	u32 *tab = NULL;
 	char *src = image->data;
 		
-	switch (ppw) {
-	case 4:
+	switch (bpp) {
+	case 8:
 		tab = cfb_tab8;
 		break;
-	case 2:
+	case 16:
 		tab = cfb_tab16;
 		break;
-	case 1:
+	case 32:
 		tab = cfb_tab32;
 		break;
 	}
@@ -264,17 +265,17 @@
 	k = image->width/ppw;
 
 	for (i = image->height; i--; ) {
-		dst = (unsigned long *) dst1;
-		
+		dst = (u32 *) dst1;
 		for (j = k; j--; ) {
 			l -= ppw;
 			end_mask = tab[(*src >> l) & bit_mask]; 
-			FB_WRITEL((end_mask & eorx)^bgx, dst++);
+			fb_writel((end_mask & eorx)^bgx, dst++);
 			if (!l) { l = 8; src++; }
 		}
+
 		if (n) {
 			end_mask = 0;	
-			ppos = LEFT_POS(bpp);
+			ppos = LEFT_POS32(bpp);
 			for (j = n; j > 0; j--) {
 				l--;
 				if (*src & (1 << l))
@@ -282,9 +283,9 @@
 				NEXT_POS(ppos, bpp);
 				if (!l) { l = 8; src++; }
 			}
-			FB_WRITEL((end_mask & eorx)^bgx, dst++);
+			fb_writel((end_mask & eorx)^bgx, dst++);
 		}
-		l -= pad;		
+		l -= pad;
 		dst1 += p->fix.line_length;	
 	}
 }	



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Re: fonts

[Geert Uytterhoeven]

On 12 Jan 2003, Antonino Daplas wrote:
> On Sun, 2003-01-12 at 03:15, Geert Uytterhoeven wrote:
> > I'm trying out different fonts with amifb (based on 2.5.56 from Linus).
> >   - PEARL8x8: OK
> >   - SUN12x22: garbage (random characters)
> >   - ProFont6x11: garbage (each different line is filled with a different
> >     character)
> >   - MINI4x6: garbage (each different line is filled with a different
> >     character)
> > 
> > At first I thought it may be caused by xres and yres not divisible by the
> > fontsize, so I tried a 800x600 mode with MINI4x6. But the problem stayed the
> > same, except that only a 640x600 window in the right part of the screen was
> > used.
> > 
> > Is my planar code in amifb to blane, or have other people seen the same?
> > 
> 
> The cfb_imageblit() function exhibited the same behavior.  I think we
> both made the wrong assumption that all monochrome bitmaps are packed. I
> think the rule is:
> 
>     The first pixel on the next scanline is always at the next byte from
>     the last pixel of the current scanline.  
> 
> So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
> last 4 are used as padding.  It's worse with a 4x6 fonts where the
> 4-bits are just duplicated in the other nibble.

Yes.

But that was not my problem. Currently accel_putcs() falls back to individual
character drawing if the fontwidth is not a multiple of 8, and reuses the same
struct fb_image for each call of fb_imageblit(). And since my fb_imageblit()
had a loop like `while (image->height--) { ... }' it failed. Not modifying the
passed struct fb_image fixed the problem. Yes, we need the const there :-)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



-------------------------------------------------------
This SF.NET email is sponsored by:
SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See!
http://www.vasoftware.com

Re: fonts

[James Simmons]

> > The cfb_imageblit() function exhibited the same behavior.  I think we
> > both made the wrong assumption that all monochrome bitmaps are packed. I
> > think the rule is:
> > 
> >     The first pixel on the next scanline is always at the next byte from
> >     the last pixel of the current scanline.  
> > 
> > So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
> > last 4 are used as padding.  It's worse with a 4x6 fonts where the
> > 4-bits are just duplicated in the other nibble.
> 
> Yes.

All the font data should be packed and byte padded at the end of each 
scanline worth of data. Also most accel engines expect the data to byte 
packed.

> But that was not my problem. Currently accel_putcs() falls back to individual
> character drawing if the fontwidth is not a multiple of 8, and reuses the same
> struct fb_image for each call of fb_imageblit(). And since my fb_imageblit()
> had a loop like `while (image->height--) { ... }' it failed. Not modifying the
> passed struct fb_image fixed the problem. Yes, we need the const there :-)

I guess I need to change that in the next set of changes.



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Re: fonts

[Geert Uytterhoeven]

On Wed, 15 Jan 2003, James Simmons wrote:
> > > The cfb_imageblit() function exhibited the same behavior.  I think we
> > > both made the wrong assumption that all monochrome bitmaps are packed. I
> > > think the rule is:
> > > 
> > >     The first pixel on the next scanline is always at the next byte from
> > >     the last pixel of the current scanline.  
> > > 
> > > So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
> > > last 4 are used as padding.  It's worse with a 4x6 fonts where the
> > > 4-bits are just duplicated in the other nibble.
> > 
> > Yes.
> 
> All the font data should be packed and byte padded at the end of each 
> scanline worth of data. Also most accel engines expect the data to byte 
> packed.

What do you mean with `each scanline worth of data'? Data for one character, or
data for the whole font (i.e. all characters)?

Currently we use the former, while e.g. AmigaOS used the latter and stored
fonts like this:

  - First line: concatenated bit string of the first lines of each character
  - Second line: concatenated bit string of the second lines of each character
  - and so on

I.e. each line looked like

    aaaaaaaaaaaabbbbbbbbbbbbccccccccccccdddddddddddd...

with a table to map between characters and starting bit index.


The former has the following advantages:
  - Character data always starts at a byte boundary
  - It's easy to store fonts in a common format (i.e. the same for both little
    and big endian, currently fonts are stored big endian)

The latter has the following advantages: 
  - Less memory waste if fontwidth % 8 != 0
  - Easy to support proportional (variable width) fonts

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



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Re: fonts

[Antonino Daplas]

On Wed, 2003-01-22 at 00:14, Geert Uytterhoeven wrote:
> On Wed, 15 Jan 2003, James Simmons wrote:
> > > > The cfb_imageblit() function exhibited the same behavior.  I think we
> > > > both made the wrong assumption that all monochrome bitmaps are packed. I
> > > > think the rule is:
> > > > 
> > > >     The first pixel on the next scanline is always at the next byte from
> > > >     the last pixel of the current scanline.  
> > > > 
> > > > So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
> > > > last 4 are used as padding.  It's worse with a 4x6 fonts where the
> > > > 4-bits are just duplicated in the other nibble.
> > > 
> > > Yes.
> > 
> > All the font data should be packed and byte padded at the end of each 
> > scanline worth of data. Also most accel engines expect the data to byte 
> > packed.
> 
> What do you mean with `each scanline worth of data'? Data for one character, or
> data for the whole font (i.e. all characters)?

I meant for each row of bits representing a pixel in a bitmap, the start
index and the size of each row will be byte-aligned.  So, the padded
version.
> 
> Currently we use the former, while e.g. AmigaOS used the latter and stored
> fonts like this:
> 
>   - First line: concatenated bit string of the first lines of each character
>   - Second line: concatenated bit string of the second lines of each character
>   - and so on
> 
> I.e. each line looked like
> 
>     aaaaaaaaaaaabbbbbbbbbbbbccccccccccccdddddddddddd...
> 

> with a table to map between characters and starting bit index.
> 
> 
> The former has the following advantages:
>   - Character data always starts at a byte boundary
>   - It's easy to store fonts in a common format (i.e. the same for both little
>     and big endian, currently fonts are stored big endian)
> 
> The latter has the following advantages: 
>   - Less memory waste if fontwidth % 8 != 0
>   - Easy to support proportional (variable width) fonts
> 

The latter is very difficult to support by most common hardware as they
require the padding.  Actually, some, maybe most, cards require more
than a byte padding. 

If we do need to support both versions, then we need extra fields to
fb_image, such as clipx1 and clipx2, where: 

	image.clipx1 = starting index;
	image.clipx2 = clipx1 + width;

(Do we also need something similar for the y coordinate?)

Using a 12x22 font as an example:

In the first (padded) version, 

	image.width = 16;
	image.clipx1 = 0;
	image.clipx2 = 12;

whereas in the second (packed) version:

	image.width = 12;
	image.clipx1 = depends on the character;
	image.clipx2 =  image.clipx1 + image.width;

I can't really think of any other way if we need to support both types
of bitmap in a device and OS independent manner.

I think I'll let you and James decide on this :-) 

Tony



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Re: fonts

[Geert Uytterhoeven]

On 22 Jan 2003, Antonino Daplas wrote:
> On Wed, 2003-01-22 at 00:14, Geert Uytterhoeven wrote:
> > On Wed, 15 Jan 2003, James Simmons wrote:
> > > > > The cfb_imageblit() function exhibited the same behavior.  I think we
> > > > > both made the wrong assumption that all monochrome bitmaps are packed. I
> > > > > think the rule is:
> > > > > 
> > > > >     The first pixel on the next scanline is always at the next byte from
> > > > >     the last pixel of the current scanline.  
> > > > > 
> > > > > So a 12x22 font has 16 bits per scanline but only 12 are usable, and the
> > > > > last 4 are used as padding.  It's worse with a 4x6 fonts where the
> > > > > 4-bits are just duplicated in the other nibble.
> > > > 
> > > > Yes.
> > > 
> > > All the font data should be packed and byte padded at the end of each 
> > > scanline worth of data. Also most accel engines expect the data to byte 
> > > packed.
> > 
> > What do you mean with `each scanline worth of data'? Data for one character, or
> > data for the whole font (i.e. all characters)?
> 
> I meant for each row of bits representing a pixel in a bitmap, the start
> index and the size of each row will be byte-aligned.  So, the padded
> version.

  [...]

> The latter is very difficult to support by most common hardware as they
> require the padding.  Actually, some, maybe most, cards require more
> than a byte padding. 

  [...]

> If we do need to support both versions, then we need extra fields to
> fb_image, such as clipx1 and clipx2, where: 
> 
> 	image.clipx1 = starting index;
> 	image.clipx2 = clipx1 + width;
> 
> (Do we also need something similar for the y coordinate?)

Or add sx and sy, cfr fb_copyarea. Makes clipping behave the same for both.

> I think I'll let you and James decide on this :-) 

I'm happy with the current scheme. I just wanted to be 100% what James meant
with `All the font data should be packed and byte padded at the end of each 
scanline worth of data.'.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds



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