Add [email protected] On Wed, Dec 21, 2022, 5:48 PM ricky rocky <[email protected]> wrote:
> Thanks for your reply soon. > > > do you want to allocate it elsewhere, not on stack? > It is OK on stack, I just want to reduce its size. Because RAM memory > capacity is 10kB left. > > > you cannot spare 16kB for rendering > Do you mean, cannot reduce 16kB size? > I saw an info that, can reduce 16kB -> 4kB, but I don't know if that will > cause any bug when rendering. > > > https://opensource.apple.com/source/X11proto/X11proto-15/freetype/freetype-2.3.5/docs/raster.txt.auto.html > > > What is the text pixel size that you need? > I'm not an expert in font pixel, could you tell me how to calculate it? > or Is it possible to know based on the information below? > ========= > I am using roboto_bold, and the height-width of largest character is 80-80 > like below > > FT_Size face_size; > struct FTC_ScalerRec_ scaler; > scaler.face_id = (FTC_FaceID)dsc->face_id; > scaler.width = 80; > scaler.height = 80; > scaler.pixel = 1; > error = FTC_Manager_LookupSize(cache_manager, &scaler, &face_size); > ========= > > > For example, for 20 pixels per EM, ... > what is EM? :( > > > On Wed, Dec 21, 2022, 12:13 PM Alexei Podtelezhnikov <[email protected]> > wrote: > >> On Tue, Dec 20, 2022 at 9:11 PM ricky rocky <[email protected]> >> wrote: >> > #define FT_RENDER_POOL_SIZE 16384L >> > >> > This definition is used in smooth/ftgrays.c/gray_convert_glyph() as a >> local buffer. >> > For my small RAM chip, it is the large size. >> >> You cannot spare 16kB for rendering. Alrighty. Or, do you want to >> allocate it elsewhere, not on stack? >> >> > For 240x320 LCD, Could I reduce this size? and how much is good? >> >> What is the text pixel size that you need? Very roughly, the number of >> nontrivial pixels is 8x the pixel size, if your font is not too fancy. >> Each gray pixel is 16 bytes on 32 bit architectures, more on 64 bits. >> >> For example, for 20 pixels per EM, you can probably get away with 2kB. >> You can use even less, but you will pay with performance. >> >> I would like to suggest doubling to pool because 32kB is reasonable these >> days. >> >> Alexei >> >
