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From: irene7 <ir...@ma...> - 2003-03-10 04:43:32
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=20Thank=20your=20for=20your=20comprehensive=20explanation=20. =20And=20i=20also=20get=20the=20information,that=20the=20embedded=20GUI=20sy= stem=20can=20support=20it's=20GUI=20rotate=2090. =20Is=20that=20true=20? =20and=20if=20it=20is=20true,=20maybe=20it's=20efficiency=20would=20be=20a=20= probelm? -----Original=20message----- From:Antonino=20Daplas=20<ad...@po...> To:ir...@ma... Cc:Linux=20Fbdev=20development=20list=20<lin...@li...= .net> Date:10=20Mar=202003=2010:06:45=20+0800 Subject:Re:=20[Linux-fbdev-devel]=20how=20to=20rotate=2090=20the=20LCD=20ima= ge On=20Sun,=202003-03-09=20at=2017:37,=20irene7=20wrote: >=20 >=20=20HI~=20 >=20 >=20=20=20=20=20i=20am=20an=20newbie.=20and=20i=20have=20a=20trouble=20: >=20=20=20=20=20my=20LCD=20driver=20is=20working=20fine=20,=20but=20the=20on= ly=20problem=20is=20the=20LCD=20image=20is=20rotate=2090. >=20=20=20=20=20what=20should=20i=20modified=20the=20driver=20to=20rotate=20= it=20back?=20 Hmm,=20a=20lot=20of=20LCD=20hardware=20have=20this=20sort=20of=20problem.=20= =20If=20you=20do=20not have=20a=20hardware=20option=20to=20change=20how=20the=20data=20is=20to=20be= =20displayed=20(such as=20rotate=2090=20degrees=20the=20other=20way),=20you=20can=20do=20at=20lea= st=20two=20things: 1.=20=20have=20your=20own=20fbcon-cfb*.c=20functions=20that=20draws,=20clear= s=20and=20moves pixels=20from=20top->bottom,=20right->left=20(90=20degrees=20CW)=20or=20bott= om->top, left->right=20(90=20degrees=20CCW).=20=20You=20may=20also=20want=20to=20pre-= rotate display->fontdata=20in=20your=20xxxfb_setup=20routine,=20so=20you=20don't=20= degrade performance.=20You=20also=20need=20to=20modify=20the=20fbcon_show_logo=20in=20= fbcon.c=20to do=20the=20same=20thing.=20=20The=20advantage=20of=20this=20method=20is=20yo= u're=20going=20to=20have a=20fairly=20efficient=20framebuffer=20console,=20the=20disadvantage=20is=20= user applications=20will=20not=20work. 2.=20=20The=20second=20method=20is=20to=20allocate=20a=20virtual=20framebuff= er.=20=20Then=20on=20a periodic=20basis,=20you=20transfer=20the=20data=20in=20the=20virtual=20frame= buffer=20to=20the actual=20framebuffer,=20doing=20the=20rotating=20on=20the=20fly.=20=20The=20= advantage=20of this=20method=20is=20user=20applications=20should=20work,=20the=20disadvanta= ge=20is=20it=20is not=20the=20most=20efficient=20method. You=20can=20look=20at:=20 ftp://ssv-embedded.de/ssv/products/trm916/sample/x86/linux/fbdev (authored=20by=20Henry) for=20a=20template=20on=20how=20to=20implement=20#2.=20=20You=20still=20have= =20to=20implement=20the rotation=20yourself.=20=20If=20you=20have=20questions=20rotating=20the=20dat= a,=20let=20me know. Tony |