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lazarus/components/aggpas/src/agg_scanline_u.pas
mattias 87711ee8b3 aggpas: undo 64bit changes 
git-svn-id: trunk@21993 -
2009-10-03 15:33:56 +00:00

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//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4 (Public License)
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Anti-Grain Geometry - Version 2.4 Release Milano 4 (AggPas 2.4 RM3)
// Pascal Port By: Milan Marusinec alias Milano
// milan@marusinec.sk
// http://www.aggpas.org
// Copyright (c) 2005-2006
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//
//----------------------------------------------------------------------------
//
// Adaptation for 32-bit screen coordinates (scanline32_u) has been sponsored by
// Liberty Technology Systems, Inc., visit http://lib-sys.com
//
// Liberty Technology Systems, Inc. is the provider of
// PostScript and PDF technology for software developers.
//
// [Pascal Port History] -----------------------------------------------------
//
// 23.06.2006-Milano: ptrcomp adjustments
// 17.01.2006-Milano: Unit port establishment
//
{ agg_scanline_u.pas }
unit
agg_scanline_u ;
INTERFACE
{$I agg_mode.inc }
uses
agg_basics ,
agg_scanline ,
agg_alpha_mask_u8 ;
{ TYPES DEFINITION }
type
//==============================================================scanline_u
//
// Unpacked scanline container class
//
// This class is used to transfer data from a scanline rasterizer
// to the rendering buffer. It's organized very simple. The class stores
// information of horizontal spans to render it into a pixel-map buffer.
// Each span has staring X, length, and an array of bytes that determine the
// cover-values for each pixel.
// Before using this class you should know the minimal and maximal pixel
// coordinates of your scanline. The protocol of using is:
// 1. reset(min_x, max_x)
// 2. add_cell() / add_span() - accumulate scanline.
// When forming one scanline the next X coordinate must be always greater
// than the last stored one, i.e. it works only with ordered coordinates.
// 3. Call finalize(y) and render the scanline.
// 3. Call reset_spans() to prepare for the new scanline.
//
// 4. Rendering:
//
// Scanline provides an iterator class that allows you to extract
// the spans and the cover values for each pixel. Be aware that clipping
// has not been done yet, so you should perform it yourself.
// Use scanline_u8::iterator to render spans:
//-------------------------------------------------------------------------
//
// int y = sl.y(); // Y-coordinate of the scanline
//
// ************************************
// ...Perform vertical clipping here...
// ************************************
//
// scanline_u8::const_iterator span = sl.begin();
//
// unsigned char* row = m_rbuf->row(y); // The the address of the beginning
// // of the current row
//
// unsigned num_spans = sl.num_spans(); // Number of spans. It's guaranteed that
// // num_spans is always greater than 0.
//
// do
// {
// const scanline_u8::cover_type* covers =
// span->covers; // The array of the cover values
//
// int num_pix = span->len; // Number of pixels of the span.
// // Always greater than 0, still it's
// // better to use "int" instead of
// // "unsigned" because it's more
// // convenient for clipping
// int x = span->x;
//
// **************************************
// ...Perform horizontal clipping here...
// ...you have x, covers, and pix_count..
// **************************************
//
// unsigned char* dst = row + x; // Calculate the start address of the row.
// // In this case we assume a simple
// // grayscale image 1-byte per pixel.
// do
// {
// *dst++ = *covers++; // Hypotetical rendering.
// }
// while(--num_pix);
//
// ++span;
// }
// while(--num_spans); // num_spans cannot be 0, so this loop is quite safe
//------------------------------------------------------------------------
//
// The question is: why should we accumulate the whole scanline when we
// could render just separate spans when they're ready?
// That's because using the scanline is generally faster. When is consists
// of more than one span the conditions for the processor cash system
// are better, because switching between two different areas of memory
// (that can be very large) occurs less frequently.
//------------------------------------------------------------------------
span_u8_ptr = ^span_u8;
span_u8 = record
x ,
len : int16;
covers : int8u_ptr;
end;
scanline_u8 = object(scanline )
m_min_x : int;
m_max_len : unsigned;
m_last_x ,
m_y : int;
m_covers : int8u_ptr;
m_spans ,
m_cur_span : span_u8_ptr;
constructor Construct;
destructor Destruct;
procedure reset(min_x ,max_x : int ); virtual;
procedure reset_spans; virtual;
procedure finalize (y_ : int ); virtual;
procedure add_cell (x : int; cover : unsigned ); virtual;
procedure add_cells(x : int; len : unsigned; covers : int8u_ptr ); virtual;
procedure add_span (x : int; len ,cover : unsigned ); virtual;
function y : int; virtual;
function num_spans : unsigned; virtual;
function begin_ : pointer; virtual;
function sz_of_span : unsigned; virtual;
end;
scanline_u8_am = object(scanline_u8 )
m_alpha_mask : alpha_mask_ptr;
constructor Construct; overload;
constructor Construct(am : alpha_mask_ptr ); overload;
procedure finalize(y_ : int ); virtual;
end;
{ GLOBAL PROCEDURES }
IMPLEMENTATION
{ LOCAL VARIABLES & CONSTANTS }
{ UNIT IMPLEMENTATION }
{ CONSTRUCT }
constructor scanline_u8.Construct;
begin
m_min_x :=0;
m_max_len:=0;
m_last_x :=$7FFFFFF0;
m_covers :=NIL;
m_spans :=NIL;
m_cur_span:=NIL;
end;
{ DESTRUCT }
destructor scanline_u8.Destruct;
begin
agg_freemem(pointer(m_spans ) ,m_max_len * sizeof(span_u8 ) );
agg_freemem(pointer(m_covers ) ,m_max_len * sizeof(int8u ) );
end;
{ RESET }
procedure scanline_u8.reset;
var
max_len : unsigned;
begin
max_len:=max_x - min_x + 2;
if max_len > m_max_len then
begin
agg_freemem(pointer(m_spans ) ,m_max_len * sizeof(span_u8 ) );
agg_freemem(pointer(m_covers ) ,m_max_len * sizeof(int8u ) );
agg_getmem(pointer(m_covers ) ,max_len * sizeof(int8u ) );
agg_getmem(pointer(m_spans ) ,max_len * sizeof(span_u8 ) );
m_max_len:=max_len;
end;
m_last_x :=$7FFFFFF0;
m_min_x :=min_x;
m_cur_span:=m_spans;
end;
{ RESET_SPANS }
procedure scanline_u8.reset_spans;
begin
m_last_x :=$7FFFFFF0;
m_cur_span:=m_spans;
end;
{ FINALIZE }
procedure scanline_u8.finalize;
begin
m_y:=y_;
end;
{ ADD_CELL }
procedure scanline_u8.add_cell;
begin
dec(x ,m_min_x );
int8u_ptr(ptrcomp(m_covers ) + x * sizeof(int8u ) )^:=int8u(cover );
if x = m_last_x + 1 then
inc(m_cur_span.len )
else
begin
inc(ptrcomp(m_cur_span ) ,sizeof(span_u8 ) );
m_cur_span.x :=int16(x + m_min_x );
m_cur_span.len:=1;
m_cur_span.covers:=int8u_ptr(ptrcomp(m_covers ) + x * sizeof(int8u ) );
end;
m_last_x:=x;
end;
{ ADD_CELLS }
procedure scanline_u8.add_cells;
begin
dec (x ,m_min_x );
move(
covers^ ,
int8u_ptr(ptrcomp(m_covers ) + x )^ ,
len * sizeof(int8u ) );
if x = m_last_x + 1 then
inc(m_cur_span.len ,int16(len ) )
else
begin
inc(ptrcomp(m_cur_span ) ,sizeof(span_u8 ) );
m_cur_span.x :=int16(x + m_min_x );
m_cur_span.len :=int16(len );
m_cur_span.covers:=int8u_ptr(ptrcomp(m_covers ) + x * sizeof(int8u ) );
end;
m_last_x:=x + len - 1;
end;
{ ADD_SPAN }
procedure scanline_u8.add_span;
begin
dec(x ,m_min_x );
fillchar(int8u_ptr(ptrcomp(m_covers ) + x * sizeof(int8u ) )^ ,len ,cover );
if x = m_last_x + 1 then
inc(m_cur_span.len ,int16(len ) )
else
begin
inc(ptrcomp(m_cur_span ) ,sizeof(span_u8 ) );
m_cur_span.x :=int16(x + m_min_x );
m_cur_span.len :=int16(len );
m_cur_span.covers:=int8u_ptr(ptrcomp(m_covers ) + x * sizeof(int8u ) );
end;
m_last_x:=x + len - 1;
end;
{ Y }
function scanline_u8.y;
begin
result:=m_y;
end;
{ NUM_SPANS }
function scanline_u8.num_spans;
begin
result:=(ptrcomp(m_cur_span ) - ptrcomp(m_spans ) ) div sizeof(span_u8 );
end;
{ BEGIN_ }
function scanline_u8.begin_;
begin
result:=span_u8_ptr(ptrcomp(m_spans ) + sizeof(span_u8 ) );
end;
{ SZ_OF_SPAN }
function scanline_u8.sz_of_span;
begin
result:=sizeof(span_u8 );
end;
{ CONSTRUCT }
constructor scanline_u8_am.Construct;
begin
inherited Construct;
m_alpha_mask:=NIL;
end;
{ CONSTRUCT }
constructor scanline_u8_am.Construct(am : alpha_mask_ptr );
begin
inherited Construct;
m_alpha_mask:=am;
end;
{ FINALIZE }
procedure scanline_u8_am.finalize;
var
span : span_u8_ptr;
ss ,count : unsigned;
begin
inherited finalize(y_ );
if m_alpha_mask <> NIL then
begin
span :=begin_;
ss :=sz_of_span;
count:=num_spans;
repeat
m_alpha_mask.combine_hspan(span.x ,y ,span.covers ,span.len );
inc(ptrcomp(span ) ,ss );
dec(count );
until count = 0;
end;
end;
END.
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