From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Linux PPC" Subject: bits_per_pixel query Date: 8 Sep 2002 16:39:36 -0000 Sender: linux-fbdev-devel-admin@lists.sourceforge.net Message-ID: <20020908163936.31266.qmail@webmail30.rediffmail.com> Reply-To: "Linux PPC" Mime-Version: 1.0 Return-path: Received: from webmail30.rediffmail.com ([202.54.124.145]) by usw-sf-list1.sourceforge.net with smtp (Exim 3.31-VA-mm2 #1 (Debian)) id 17o56u-0006A1-00 for ; Sun, 08 Sep 2002 09:40:33 -0700 Content-Disposition: inline Errors-To: linux-fbdev-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; format=flowed; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-fbdev-devel@lists.sourceforge.net Hello there, I had some doubts regarding the framebuffer struct usage. As I understand, the buffer is at fb_info.screen_base and the size of the buffer is (hres * vres * bits_per_pixel )/8. The state of the pixel at location (x,y), would be represented by the value of byte at screen_base + ((y*hres + x) * bits_per_pixel)/8. If the display is 8 bit, then it would require only a byte to represent the value of the pixel. If it were 24 bit, then it would require 3 bytes, and so on. Is that right? What would happen, to the size required for the buffer, if the display requires, say 12 bits per pixel, or 18 bits? So, if I were to set all the bytes after screen_base uptil screen_base + (hres*vres*bits_per_pixel/8) to zeros, then I would get a black screen. Is that right? I'm asking cos, I'm workin on a framebuffer support for an LCD panel, and am making the above assumption which doesn't seem happening. - navin. __________________________________________________________ Give your Company an email address like ravi @ ravi-exports.com. Sign up for Rediffmail Pro today! Know more. http://www.rediffmailpro.com/signup/ ------------------------------------------------------- This sf.net email is sponsored by: OSDN - Tired of that same old cell phone? Get a new here for FREE! https://www.inphonic.com/r.asp?r=sourceforge1&refcode1=vs3390