Home » Archimedes archive » Acorn Computing » 1995 01.adf » 9501 » TechForum/Thumbnails/Thumbs/!Thumbs/!Help
TechForum/Thumbnails/Thumbs/!Thumbs/!Help
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Acorn Computing » 1995 01.adf » 9501 |
| Filename: | TechForum/Thumbnails/Thumbs/!Thumbs/!Help |
| Read OK: | ✔ |
| File size: | 0791 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
Thumbnail making demo:
See magazine for details of what this is all about & move directory 'Thumbs'
to a writable medium before running !Thumbs.
Demo reads sprite file 'Input' from !Thumbs parent directory. Attempts to
create a thumbnail for each sprite within it - only 256 colour sources can
currently be dealt with {modify c.minisprs function 'plotinto', if you want
to handle other source sprites}. Saves all resulting thumbnails to sprite
file 'Output' in same directory as 'Input'.
Note, thumbnail mode will be based on current screen mode, such that if
current mode has pixel aspect 1:2, then so will thumbnail, else thumbnail
gets pixel aspect 1:1.
Code allows above to be changed so that pixel aspect is based on the source
sprite pixel aspect {call sprsdisp_miniusesourceaspect(TRUE) prior to
mini_make}, though you could of course adopt any method you like.
Thumbnails maintain aspect ratio of source, & are fitted to lie within a
square of side SDmaxsize os units. SDmaxsize is an int variable. In this
demo it can be modified by altering the value following !RunImage in the
last line of the !Run file (it should be a multiple of 8).
Note, time taken by code is proportionate to thumbnail size, & almost
entirely independent of source size. For SDmaxsize=128, times are typically
low & much quicker than ChangeFSI, however you could increase speed still
further by recoding 'plotprocess' in assembler.
If you use this code in your own programs where speed is important & where
many mini sprites are being made in one batch, be careful about time taken
to extend the miniarea sprite area upon each mini_make call.
The total time used to flex_extend it may be greater than that required by
all other computations! - in such a situation it is better to flex_extend it
prior to processing the batch, in order to leave enough free space in the
mini_area for all the expected mini sprites. This is not done in this demo.
00000000 0a 54 68 75 6d 62 6e 61 69 6c 20 6d 61 6b 69 6e |.Thumbnail makin|
00000010 67 20 64 65 6d 6f 3a 0a 0a 53 65 65 20 6d 61 67 |g demo:..See mag|
00000020 61 7a 69 6e 65 20 66 6f 72 20 64 65 74 61 69 6c |azine for detail|
00000030 73 20 6f 66 20 77 68 61 74 20 74 68 69 73 20 69 |s of what this i|
00000040 73 20 61 6c 6c 20 61 62 6f 75 74 20 26 20 6d 6f |s all about & mo|
00000050 76 65 20 64 69 72 65 63 74 6f 72 79 20 27 54 68 |ve directory 'Th|
00000060 75 6d 62 73 27 0a 74 6f 20 61 20 77 72 69 74 61 |umbs'.to a writa|
00000070 62 6c 65 20 6d 65 64 69 75 6d 20 62 65 66 6f 72 |ble medium befor|
00000080 65 20 72 75 6e 6e 69 6e 67 20 21 54 68 75 6d 62 |e running !Thumb|
00000090 73 2e 0a 0a 44 65 6d 6f 20 72 65 61 64 73 20 73 |s...Demo reads s|
000000a0 70 72 69 74 65 20 66 69 6c 65 20 27 49 6e 70 75 |prite file 'Inpu|
000000b0 74 27 20 66 72 6f 6d 20 21 54 68 75 6d 62 73 20 |t' from !Thumbs |
000000c0 70 61 72 65 6e 74 20 64 69 72 65 63 74 6f 72 79 |parent directory|
000000d0 2e 20 41 74 74 65 6d 70 74 73 20 74 6f 0a 63 72 |. Attempts to.cr|
000000e0 65 61 74 65 20 61 20 74 68 75 6d 62 6e 61 69 6c |eate a thumbnail|
000000f0 20 66 6f 72 20 65 61 63 68 20 73 70 72 69 74 65 | for each sprite|
00000100 20 77 69 74 68 69 6e 20 69 74 20 2d 20 6f 6e 6c | within it - onl|
00000110 79 20 32 35 36 20 63 6f 6c 6f 75 72 20 73 6f 75 |y 256 colour sou|
00000120 72 63 65 73 20 63 61 6e 0a 63 75 72 72 65 6e 74 |rces can.current|
00000130 6c 79 20 62 65 20 64 65 61 6c 74 20 77 69 74 68 |ly be dealt with|
00000140 20 7b 6d 6f 64 69 66 79 20 63 2e 6d 69 6e 69 73 | {modify c.minis|
00000150 70 72 73 20 66 75 6e 63 74 69 6f 6e 20 27 70 6c |prs function 'pl|
00000160 6f 74 69 6e 74 6f 27 2c 20 69 66 20 79 6f 75 20 |otinto', if you |
00000170 77 61 6e 74 0a 74 6f 20 68 61 6e 64 6c 65 20 6f |want.to handle o|
00000180 74 68 65 72 20 73 6f 75 72 63 65 20 73 70 72 69 |ther source spri|
00000190 74 65 73 7d 2e 20 53 61 76 65 73 20 61 6c 6c 20 |tes}. Saves all |
000001a0 72 65 73 75 6c 74 69 6e 67 20 74 68 75 6d 62 6e |resulting thumbn|
000001b0 61 69 6c 73 20 74 6f 20 73 70 72 69 74 65 0a 66 |ails to sprite.f|
000001c0 69 6c 65 20 27 4f 75 74 70 75 74 27 20 69 6e 20 |ile 'Output' in |
000001d0 73 61 6d 65 20 64 69 72 65 63 74 6f 72 79 20 61 |same directory a|
000001e0 73 20 27 49 6e 70 75 74 27 2e 0a 0a 4e 6f 74 65 |s 'Input'...Note|
000001f0 2c 20 74 68 75 6d 62 6e 61 69 6c 20 6d 6f 64 65 |, thumbnail mode|
00000200 20 77 69 6c 6c 20 62 65 20 62 61 73 65 64 20 6f | will be based o|
00000210 6e 20 63 75 72 72 65 6e 74 20 73 63 72 65 65 6e |n current screen|
00000220 20 6d 6f 64 65 2c 20 73 75 63 68 20 74 68 61 74 | mode, such that|
00000230 20 69 66 0a 63 75 72 72 65 6e 74 20 6d 6f 64 65 | if.current mode|
00000240 20 68 61 73 20 70 69 78 65 6c 20 61 73 70 65 63 | has pixel aspec|
00000250 74 20 31 3a 32 2c 20 74 68 65 6e 20 73 6f 20 77 |t 1:2, then so w|
00000260 69 6c 6c 20 74 68 75 6d 62 6e 61 69 6c 2c 20 65 |ill thumbnail, e|
00000270 6c 73 65 20 74 68 75 6d 62 6e 61 69 6c 0a 67 65 |lse thumbnail.ge|
00000280 74 73 20 70 69 78 65 6c 20 61 73 70 65 63 74 20 |ts pixel aspect |
00000290 31 3a 31 2e 0a 0a 43 6f 64 65 20 61 6c 6c 6f 77 |1:1...Code allow|
000002a0 73 20 61 62 6f 76 65 20 74 6f 20 62 65 20 63 68 |s above to be ch|
000002b0 61 6e 67 65 64 20 73 6f 20 74 68 61 74 20 70 69 |anged so that pi|
000002c0 78 65 6c 20 61 73 70 65 63 74 20 69 73 20 62 61 |xel aspect is ba|
000002d0 73 65 64 20 6f 6e 20 74 68 65 20 73 6f 75 72 63 |sed on the sourc|
000002e0 65 0a 73 70 72 69 74 65 20 70 69 78 65 6c 20 61 |e.sprite pixel a|
000002f0 73 70 65 63 74 20 7b 63 61 6c 6c 20 73 70 72 73 |spect {call sprs|
00000300 64 69 73 70 5f 6d 69 6e 69 75 73 65 73 6f 75 72 |disp_miniusesour|
00000310 63 65 61 73 70 65 63 74 28 54 52 55 45 29 20 70 |ceaspect(TRUE) p|
00000320 72 69 6f 72 20 74 6f 0a 6d 69 6e 69 5f 6d 61 6b |rior to.mini_mak|
00000330 65 7d 2c 20 74 68 6f 75 67 68 20 79 6f 75 20 63 |e}, though you c|
00000340 6f 75 6c 64 20 6f 66 20 63 6f 75 72 73 65 20 61 |ould of course a|
00000350 64 6f 70 74 20 61 6e 79 20 6d 65 74 68 6f 64 20 |dopt any method |
00000360 79 6f 75 20 6c 69 6b 65 2e 0a 0a 54 68 75 6d 62 |you like...Thumb|
00000370 6e 61 69 6c 73 20 6d 61 69 6e 74 61 69 6e 20 61 |nails maintain a|
00000380 73 70 65 63 74 20 72 61 74 69 6f 20 6f 66 20 73 |spect ratio of s|
00000390 6f 75 72 63 65 2c 20 26 20 61 72 65 20 66 69 74 |ource, & are fit|
000003a0 74 65 64 20 74 6f 20 6c 69 65 20 77 69 74 68 69 |ted to lie withi|
000003b0 6e 20 61 0a 73 71 75 61 72 65 20 6f 66 20 73 69 |n a.square of si|
000003c0 64 65 20 53 44 6d 61 78 73 69 7a 65 20 6f 73 20 |de SDmaxsize os |
000003d0 75 6e 69 74 73 2e 20 53 44 6d 61 78 73 69 7a 65 |units. SDmaxsize|
000003e0 20 69 73 20 61 6e 20 69 6e 74 20 76 61 72 69 61 | is an int varia|
000003f0 62 6c 65 2e 20 49 6e 20 74 68 69 73 0a 64 65 6d |ble. In this.dem|
00000400 6f 20 69 74 20 63 61 6e 20 62 65 20 6d 6f 64 69 |o it can be modi|
00000410 66 69 65 64 20 62 79 20 61 6c 74 65 72 69 6e 67 |fied by altering|
00000420 20 74 68 65 20 76 61 6c 75 65 20 66 6f 6c 6c 6f | the value follo|
00000430 77 69 6e 67 20 21 52 75 6e 49 6d 61 67 65 20 69 |wing !RunImage i|
00000440 6e 20 74 68 65 0a 6c 61 73 74 20 6c 69 6e 65 20 |n the.last line |
00000450 6f 66 20 74 68 65 20 21 52 75 6e 20 66 69 6c 65 |of the !Run file|
00000460 20 28 69 74 20 73 68 6f 75 6c 64 20 62 65 20 61 | (it should be a|
00000470 20 6d 75 6c 74 69 70 6c 65 20 6f 66 20 38 29 2e | multiple of 8).|
00000480 0a 0a 4e 6f 74 65 2c 20 74 69 6d 65 20 74 61 6b |..Note, time tak|
00000490 65 6e 20 62 79 20 63 6f 64 65 20 69 73 20 70 72 |en by code is pr|
000004a0 6f 70 6f 72 74 69 6f 6e 61 74 65 20 74 6f 20 74 |oportionate to t|
000004b0 68 75 6d 62 6e 61 69 6c 20 73 69 7a 65 2c 20 26 |humbnail size, &|
000004c0 20 61 6c 6d 6f 73 74 0a 65 6e 74 69 72 65 6c 79 | almost.entirely|
000004d0 20 69 6e 64 65 70 65 6e 64 65 6e 74 20 6f 66 20 | independent of |
000004e0 73 6f 75 72 63 65 20 73 69 7a 65 2e 20 46 6f 72 |source size. For|
000004f0 20 53 44 6d 61 78 73 69 7a 65 3d 31 32 38 2c 20 | SDmaxsize=128, |
00000500 74 69 6d 65 73 20 61 72 65 20 74 79 70 69 63 61 |times are typica|
00000510 6c 6c 79 0a 6c 6f 77 20 26 20 6d 75 63 68 20 71 |lly.low & much q|
00000520 75 69 63 6b 65 72 20 74 68 61 6e 20 43 68 61 6e |uicker than Chan|
00000530 67 65 46 53 49 2c 20 68 6f 77 65 76 65 72 20 79 |geFSI, however y|
00000540 6f 75 20 63 6f 75 6c 64 20 69 6e 63 72 65 61 73 |ou could increas|
00000550 65 20 73 70 65 65 64 20 73 74 69 6c 6c 0a 66 75 |e speed still.fu|
00000560 72 74 68 65 72 20 62 79 20 72 65 63 6f 64 69 6e |rther by recodin|
00000570 67 20 27 70 6c 6f 74 70 72 6f 63 65 73 73 27 20 |g 'plotprocess' |
00000580 69 6e 20 61 73 73 65 6d 62 6c 65 72 2e 0a 0a 49 |in assembler...I|
00000590 66 20 79 6f 75 20 75 73 65 20 74 68 69 73 20 63 |f you use this c|
000005a0 6f 64 65 20 69 6e 20 79 6f 75 72 20 6f 77 6e 20 |ode in your own |
000005b0 70 72 6f 67 72 61 6d 73 20 77 68 65 72 65 20 73 |programs where s|
000005c0 70 65 65 64 20 69 73 20 69 6d 70 6f 72 74 61 6e |peed is importan|
000005d0 74 20 26 20 77 68 65 72 65 0a 6d 61 6e 79 20 6d |t & where.many m|
000005e0 69 6e 69 20 73 70 72 69 74 65 73 20 61 72 65 20 |ini sprites are |
000005f0 62 65 69 6e 67 20 6d 61 64 65 20 69 6e 20 6f 6e |being made in on|
00000600 65 20 62 61 74 63 68 2c 20 62 65 20 63 61 72 65 |e batch, be care|
00000610 66 75 6c 20 61 62 6f 75 74 20 74 69 6d 65 20 74 |ful about time t|
00000620 61 6b 65 6e 0a 74 6f 20 65 78 74 65 6e 64 20 74 |aken.to extend t|
00000630 68 65 20 6d 69 6e 69 61 72 65 61 20 73 70 72 69 |he miniarea spri|
00000640 74 65 20 61 72 65 61 20 75 70 6f 6e 20 65 61 63 |te area upon eac|
00000650 68 20 6d 69 6e 69 5f 6d 61 6b 65 20 63 61 6c 6c |h mini_make call|
00000660 2e 0a 0a 54 68 65 20 74 6f 74 61 6c 20 74 69 6d |...The total tim|
00000670 65 20 75 73 65 64 20 74 6f 20 66 6c 65 78 5f 65 |e used to flex_e|
00000680 78 74 65 6e 64 20 69 74 20 6d 61 79 20 62 65 20 |xtend it may be |
00000690 67 72 65 61 74 65 72 20 74 68 61 6e 20 74 68 61 |greater than tha|
000006a0 74 20 72 65 71 75 69 72 65 64 20 62 79 0a 61 6c |t required by.al|
000006b0 6c 20 6f 74 68 65 72 20 63 6f 6d 70 75 74 61 74 |l other computat|
000006c0 69 6f 6e 73 21 20 2d 20 69 6e 20 73 75 63 68 20 |ions! - in such |
000006d0 61 20 73 69 74 75 61 74 69 6f 6e 20 69 74 20 69 |a situation it i|
000006e0 73 20 62 65 74 74 65 72 20 74 6f 20 66 6c 65 78 |s better to flex|
000006f0 5f 65 78 74 65 6e 64 20 69 74 0a 70 72 69 6f 72 |_extend it.prior|
00000700 20 74 6f 20 70 72 6f 63 65 73 73 69 6e 67 20 74 | to processing t|
00000710 68 65 20 62 61 74 63 68 2c 20 69 6e 20 6f 72 64 |he batch, in ord|
00000720 65 72 20 74 6f 20 6c 65 61 76 65 20 65 6e 6f 75 |er to leave enou|
00000730 67 68 20 66 72 65 65 20 73 70 61 63 65 20 69 6e |gh free space in|
00000740 20 74 68 65 0a 6d 69 6e 69 5f 61 72 65 61 20 66 | the.mini_area f|
00000750 6f 72 20 61 6c 6c 20 74 68 65 20 65 78 70 65 63 |or all the expec|
00000760 74 65 64 20 6d 69 6e 69 20 73 70 72 69 74 65 73 |ted mini sprites|
00000770 2e 20 54 68 69 73 20 69 73 20 6e 6f 74 20 64 6f |. This is not do|
00000780 6e 65 20 69 6e 20 74 68 69 73 20 64 65 6d 6f 2e |ne in this demo.|
00000790 0a |.|
00000791 
.