To summarize, if I may: for an RGBA image having Height rows, each Width
pixels wide,
Pitch = 4 x Width + Pad (4 x 8 + 0 = 32 bytes per row)
Size = Pitch x Height (32 x 16 = 512 bytes per image)
-----Original Message-----
From: freetype-bounces+yves.daoust=visionforvision...@nongnu.org
[mailto:freetype-bounces+yves.daoust=visionforvision...@nongnu.org] On
Behalf Of Glynn Clements
Sent: Tuesday, June 18, 2013 7:21 PM
To: First Last
Cc: xorg@lists.x.org; freet...@nongnu.org
Subject: Re: [ft] need help with freetype + xlib.
First Last wrote:
> Hi, I try to use freetype with xlib, I , I need to pass a char type
> array (RGBA/pixel) to a xlib function.
>
> from freetype I got :
>
> face->glyph->bitmap.pixel_mode = 2
> so if I understood corectly in face->glyph->bitmap.buffer datas are stored
in gray level.
> face->glyph->bitmap.rows=16
> face->glyph->bitmap.width=8
> face->glyph->bitmap.pitch=8
>
> so I guess, length of face->glyph->bitmap.buffer = 1(gray
> lvl)*16(width)*8(rows)=128 unsigned chars, right ?
Right answer, wrong reasoning; width should be replaced by pitch. The two
values may differ if there is padding between lines.
> then I create an array of char for xlib from
> face->glyph->bitmap.buffer
>
> for(i=0;i<128;i++){
> Xdata[4*i] = face->glyph->bitmap.buffer[i];
> Xdata[4*i+1] = face->glyph->bitmap.buffer[i];
> Xdata[4*i+2] = face->glyph->bitmap.buffer[i];
> Xdata[4*i+3] = 255;
> } and I try to create a XImage :
> ximage = XCreateImage(display, DefaultVisual(display,0), 24,
> ZPixmap, 0,
> &Xdata[0], 8/*rows*/,
> 16/*width*/, 32/*RGBA*/, 8/*pitch??*/);
The last argument (bytes_per_line) should be 32 (8 pixels wide at 4 bytes
per pixel).
--
Glynn Clements <gl...@gclements.plus.com>
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