[imager.git] / design / draw.pod

=head1 NAME

draw.pod - overview of planned drawing changes

=head1 SYNOPSIS

  fix the processing done by the current combine modes
  combine modes for most drawing operations
  thick lines

=head1 combine mode fixes

Currently:

=over

=item *

the calculations are just wrong

=item *

they don't handle adapting to the target channel count

=back

To do:

=over

=item *

add a render function that calls the fill function then applies it to
the target based on the combine mode.

=item *

modify fill functions to always produce RGBA

=item *

have the combine mode functions just generate the color, the render
function can then alpha adjust it and apply it to the target

=back

=head1 combine modes for drawing functions

=over

=item *

write versions of each function that take a combine mode

=back

=head1 thick lines

Two possible approaches:

=over

=item *

given a polyline, generate a polygon for the entire shape - more
complex, overlap problems

=item *

given a polyline, generate polygons for each segment, draw to a work
image and use that to compose the fill - possible problems joining the
segments

=back
Commit	Line	Data
9b1ec2b8 TC	1	=head1 NAME
	2
	3	draw.pod - overview of planned drawing changes
	4
	5	=head1 SYNOPSIS
	6
	7	fix the processing done by the current combine modes
	8	combine modes for most drawing operations
	9	thick lines
	10
	11	=head1 combine mode fixes
	12
	13	Currently:
	14
	15	=over
	16
	17	=item *
	18
	19	the calculations are just wrong
	20
	21	=item *
	22
	23	they don't handle adapting to the target channel count
	24
	25	=back
	26
	27	To do:
	28
	29	=over
	30
	31	=item *
	32
	33	add a render function that calls the fill function then applies it to
	34	the target based on the combine mode.
	35
	36	=item *
	37
	38	modify fill functions to always produce RGBA
	39
	40	=item *
	41
	42	have the combine mode functions just generate the color, the render
	43	function can then alpha adjust it and apply it to the target
	44
	45	=back
	46
	47	=head1 combine modes for drawing functions
	48
	49	=over
	50
	51	=item *
	52
	53	write versions of each function that take a combine mode
	54
	55	=back
	56
	57	=head1 thick lines
	58
	59	Two possible approaches:
	60
	61	=over
	62
	63	=item *
	64
65	given a polyline, generate a polygon for the entire shape - more
66	complex, overlap problems
67
68	=item *
69
70	given a polyline, generate polygons for each segment, draw to a work
71	image and use that to compose the fill - possible problems joining the
72	segments
73
74	=back