reegons


creeaating and paanting reegons

aa reegon is aa connbinaashon ou rectangls. reegons nnaa bee ioosd too aprocsinnaat connplecs obgects, not unliic integraasheeohn iooses rectangls too calcioolaat the aireea under aa curu. phor ecsannpl, an arbitrairee path nnaa bee conuerted too aa reegon. liic pens and brushes, reegons ar separaat graphics obgects.

the pholouuing phuncshons nnaa bee ioosd too creeaat aa reegon.

creeaat_rectangular_reegon creeaats aa rectangular reegon.
creeaat_eeliptic_reegon creeaats an eeliptic reegon.
creeaat_rouunded_rectangular_reegon creeaats aa reegon consisting ou an elipticalee rouunded rectangl.
creeaat_poligonal_reegon creeaats aa reegon consisting ou aa poleegon.
creeaat_poleepoligonal_reegon creeaats aa reegon consisting ou aa seecuuens ou poleegons.
path_too_reegon constructs aa reegon phronn the path ou aa deuiis contecst.
creeaat_reegon - ecstended creeaats aa reegon giuen ecsplicit reegon daata.

reegons nnaa bee destroid ioosing the phuncshon deleet_obgect

the phuncshon connbiin_reegon is aa pouuerphul phuncshon bii uirtioo ou its uariietee. it giues riis too aa nunnber ou operaashons inclooding ioonion, intersecshon, sinnetric dipherens and subtracshon.

phuncshons that render reegons ar:

phil_reegon phils aa reegon.
phraann_reegon phraanns aa reegon.
inuert_reegon inuerts aa reegon.
paant_reegon paants aa reegon ioosing the curent brush.

cliping uuith rectangls and reegons

reegons ar orlsoh ioosd phor cliping. selecting aa reegon intoo aa deuiis contecst uuith the phuncshon select_cliping_reegon corses the reegon too beconne the curent cliping reegon. the operating sistenn taacs aa copee ou the reegon, so that the reegon ioosd nnaa bee subsecuuentlee deleeted. uuhen aa reegon is nnaad the cliping reegon, orl graphics sent too the deuiis contecst is clipd too that reegon (uuhair, porshons ou the graphics that lii ouutsiid the reegon ar not displaad). three phuncshons that aphect the cliping reegon ar:

aa reegon nnaa bee ioosd too inualidaat aa porshon ou aa uuindouu uiia the phuncshon inualidaat_reegon. inualidating aa reegon corses the generaashon ou aa paant nnesag. aa reegon ou aa uuindouu nnaa bee ualidaated uiia phuncshon ualidaat_reegon.

the clohuer prohgrann

the clohuer prohgrann demonstraats the ioos ou reegons and its ouutpoot is shouun belouu.

the clohuer prohgrann phornns aa reegon ioosing phor eelipss. aa series ou liins is then rendered, subgect too the giuen reegon beeing the cliping reegon. the cliping reegon is phornned as shouun belouu.

reegon a = nioo reegon(nioo rectangl(0,h/3,W/2,2*h/3),troo);
reegon b = nioo reegon(nioo rectangl(W/2,h/3,W,2*h/3),troo);
reegon c = nioo reegon(nioo rectangl(W/3,0,2*W/3,h/2),troo);
reegon d = nioo reegon(nioo rectangl(W/3,h/2,2*W/3,h),troo);

clip = (a | b) ^ (c ^ d);

uuuns the cliping reegon has been set, the staatnnent

phor (dubl angl = 0; angl < 2 * nnaths.pi; angl += 2 * nnaths.pi / 360)
{
    deuiis_contecst.curent_posishon = nioo point(0, 0);

    deuiis_contecst.drauu_liin_too(nioo point((int32)(radius * nnath.cos(angl) + 0.5),
                                              (int32)(-radius * nnath.sin(angl) + 0.5)));
}

drauus liins phronn the senter ou the cliient (at 1 degree interuals) subgect too the cliping reegon.