plotters.c

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/*
 * Copyright 2008-09, 2012-13 Chris Young <chris@unsatisfactorysoftware.co.uk>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "amiga/os3support.h"
 
#include <proto/exec.h>
#include <proto/intuition.h>
#include <proto/layers.h>
#include <proto/graphics.h>
 
#include <intuition/intuition.h>
#include <graphics/rpattr.h>
#include <graphics/gfxmacros.h>
#include <graphics/gfxbase.h>
 
#ifdef __amigaos4__
#include <graphics/blitattr.h>
#include <graphics/composite.h>
#endif
 
#include <math.h>
#include <assert.h>
#include <stdlib.h>
 
#include "utils/nsoption.h"
#include "utils/utils.h"
#include "utils/log.h"
#include "netsurf/css.h"
#include "netsurf/mouse.h"
#include "netsurf/window.h"
 
#include "amiga/plotters.h"
#include "amiga/bitmap.h"
#include "amiga/font.h"
#include "amiga/gui.h"
#include "amiga/memory.h"
#include "amiga/misc.h"
#include "amiga/rtg.h"
#include "amiga/utf8.h"
 
HOOKF(void, ami_bitmap_tile_hook, struct RastPort *, rp, struct BackFillMessage *);
 
struct bfbitmap {
        struct BitMap *bm;
        ULONG width;
        ULONG height;
        int offsetx;
        int offsety;
        APTR mask;
        bool palette_mapped;
};
 
struct ami_plot_pen {
        struct MinNode node;
        ULONG pen;
};
 
struct bez_point {
        float x;
        float y;
};
 
struct gui_globals {
        struct BitMap *bm;
        struct RastPort *rp;
        struct Layer_Info *layerinfo;
        APTR areabuf;
        APTR tmprasbuf;
        struct Rectangle rect;
        struct MinList *shared_pens;
        bool managed_pen_list;
        bool palette_mapped;
        ULONG apen;
        ULONG open;
        LONG apen_num;
        LONG open_num;
        int width;  /* size of bm and    */
        int height; /* associated memory */
};
 
static int init_layers_count = 0;
static APTR pool_pens = NULL;
static bool palette_mapped = true; /* palette-mapped state for the screen */
 
#ifndef M_PI /* For some reason we don't always get this from math.h */
#define M_PI            3.14159265358979323846
#endif
 
#define PATT_DOT  0xAAAA
#define PATT_DASH 0xCCCC
#define PATT_LINE 0xFFFF
 
/* This defines the size of the list for Area* functions.
   25000 = 5000 vectors
  */
#define AREA_SIZE 25000
 
struct gui_globals *ami_plot_ra_alloc(ULONG width, ULONG height, bool force32bit, bool alloc_pen_list)
{
        /* init shared bitmaps */
        int depth = 32;
        struct BitMap *friend = NULL;
        struct Screen *scrn = ami_gui_get_screen();
 
        struct gui_globals *gg = malloc(sizeof(struct gui_globals));
 
        if(force32bit == false) depth = GetBitMapAttr(scrn->RastPort.BitMap, BMA_DEPTH);
        NSLOG(netsurf, INFO, "Screen depth = %d", depth);
 
#ifdef __amigaos4__
        if(depth < 16) {
                gg->palette_mapped = true;
                if(force32bit == false) palette_mapped = true;
                
                bitmap_set_format(&(bitmap_fmt_t) {
                        .layout = BITMAP_LAYOUT_ARGB8888,
                        .pma = true,
                });
        
                NSLOG(netsurf, INFO, "Set bitmap format to 0xAARRGGBB (native endian) (PMA)");
                
        } else {
                gg->palette_mapped = false;
                
                bitmap_set_format(&(bitmap_fmt_t) {
                        .layout = BITMAP_LAYOUT_ARGB8888,
                        .pma = false,
                });
        
                NSLOG(netsurf, INFO, "Set bitmap format to 0xAARRGGBB (native endian)");
 
        }
#else
        bitmap_set_format(&(bitmap_fmt_t) {
                .layout = BITMAP_LAYOUT_ARGB8888,
                .pma = true,
        });
        
        NSLOG(netsurf, INFO, "Set bitmap format to 0xAARRGGBB (native endian) (PMA)");
 
 
        /* Friend BitMaps are weird.
         * For OS4, we shouldn't use a friend BitMap here (see below).
         * For OS3 AGA, we get no display blitted if we use a friend BitMap,
         * however on RTG it seems to be a benefit.
         */
        if(nsoption_bool(friend_bitmap) == true) {
                friend = scrn->RastPort.BitMap;
        } else {
                /* Force friend BitMaps on for obvious RTG screens under OS3.
                 * If we get a bit smarter about this we can lose the user option. */
                if((depth > 8) && (force32bit == false)) friend = scrn->RastPort.BitMap;
        }
 
        if(depth < 16) {
                gg->palette_mapped = true;
                if(force32bit == false) palette_mapped = true;
        } else {
                gg->palette_mapped = false;
        }
#endif
 
        /* Probably need to fix this next line */
        if(gg->palette_mapped == true) nsoption_set_bool(font_antialiasing, false);
 
        if(!width) width = nsoption_int(redraw_tile_size_x);
        if(!height) height = nsoption_int(redraw_tile_size_y);
        gg->width = width;
        gg->height = height;
 
        gg->layerinfo = NewLayerInfo();
        gg->areabuf = malloc(AREA_SIZE);
 
        /* OS3/AGA requires this to be in chip mem.  RTG would probably rather it wasn't. */
        gg->tmprasbuf = ami_memory_chip_alloc(width * height);
 
        if(gg->palette_mapped == true) {
                gg->bm = AllocBitMap(width, height, depth, 0, friend);
        } else {
#ifdef __amigaos4__
                /* Screen depth is reported as 24 even when it's actually 32-bit.
                 * We get freezes and other problems on OS4 if we befriend at any
                 * other depths, hence this check.
                 * \todo use friend BitMaps but avoid CompositeTags() at non-32-bit
                 * as that seems to be the cause of the problems.
                 */
                if((depth >= 24) && (force32bit == false)) friend = scrn->RastPort.BitMap;
#endif
                gg->bm = ami_rtg_allocbitmap(width, height, 32, 0, friend, RGBFB_A8R8G8B8);
        }
 
        if(!gg->bm) amiga_warn_user("NoMemory","");
 
        gg->rp = malloc(sizeof(struct RastPort));
        if(!gg->rp) amiga_warn_user("NoMemory","");
 
        InitRastPort(gg->rp);
        gg->rp->BitMap = gg->bm;
 
        SetDrMd(gg->rp,BGBACKFILL);
 
        gg->rp->Layer = CreateUpfrontLayer(gg->layerinfo,gg->rp->BitMap,0,0,
                                        width-1, height-1, LAYERSIMPLE, NULL);
 
        InstallLayerHook(gg->rp->Layer,LAYERS_NOBACKFILL);
 
        gg->rp->AreaInfo = malloc(sizeof(struct AreaInfo));
        if((!gg->areabuf) || (!gg->rp->AreaInfo))       amiga_warn_user("NoMemory","");
 
        InitArea(gg->rp->AreaInfo, gg->areabuf, AREA_SIZE/5);
 
        gg->rp->TmpRas = malloc(sizeof(struct TmpRas));
        if((!gg->tmprasbuf) || (!gg->rp->TmpRas))       amiga_warn_user("NoMemory","");
 
        InitTmpRas(gg->rp->TmpRas, gg->tmprasbuf, width*height);
 
        gg->shared_pens = NULL;
        gg->managed_pen_list = false;
 
        if(gg->palette_mapped == true) {
                if(pool_pens == NULL) {
                        pool_pens = ami_memory_itempool_create(sizeof(struct ami_plot_pen));
                }
 
                if(alloc_pen_list == true) {
                        gg->shared_pens = ami_AllocMinList();
                        gg->managed_pen_list = true;
                }
        }
 
        gg->apen = 0x00000000;
        gg->open = 0x00000000;
        gg->apen_num = -1;
        gg->open_num = -1;
 
        init_layers_count++;
        NSLOG(netsurf, INFO, "Layer initialised (total: %d)",
              init_layers_count);
 
        return gg;
}
 
void ami_plot_ra_free(struct gui_globals *gg)
{
        init_layers_count--;
 
        if(init_layers_count < 0) return;
 
        if((init_layers_count == 0) && (pool_pens != NULL)) {
                ami_memory_itempool_delete(pool_pens);
                pool_pens = NULL;
        }
 
        if(gg->rp) {
                if(gg->rp->Layer != NULL) DeleteLayer(0, gg->rp->Layer);
                free(gg->rp->TmpRas);
                free(gg->rp->AreaInfo);
                free(gg->rp);
        }
 
        ami_memory_chip_free(gg->tmprasbuf);
        free(gg->areabuf);
        DisposeLayerInfo(gg->layerinfo);
        if(gg->bm) ami_rtg_freebitmap(gg->bm);
 
        if(gg->managed_pen_list == true) {
                ami_plot_release_pens(gg->shared_pens);
                free(gg->shared_pens);
                gg->shared_pens = NULL;
        }
 
        free(gg);
}
 
struct RastPort *ami_plot_ra_get_rastport(struct gui_globals *gg)
{
        return gg->rp;
}
 
struct BitMap *ami_plot_ra_get_bitmap(struct gui_globals *gg)
{
        return gg->bm;
}
 
void ami_plot_ra_get_size(struct gui_globals *gg, int *width, int *height)
{
        *width = gg->width;
        *height = gg->height;
}
 
void ami_plot_ra_set_pen_list(struct gui_globals *gg, struct MinList *pen_list)
{
        gg->shared_pens = pen_list;
}
 
void ami_clearclipreg(struct gui_globals *gg)
{
        struct Region *reg = NULL;
        struct Screen *scrn = ami_gui_get_screen();
 
        reg = InstallClipRegion(gg->rp->Layer,NULL);
        if(reg) DisposeRegion(reg);
 
        gg->rect.MinX = 0;
        gg->rect.MinY = 0;
        gg->rect.MaxX = scrn->Width-1;
        gg->rect.MaxY = scrn->Height-1;
 
        gg->apen = 0x00000000;
        gg->open = 0x00000000;
        gg->apen_num = -1;
        gg->open_num = -1;
}
 
static ULONG ami_plot_obtain_pen(struct MinList *shared_pens, ULONG colr)
{
        struct ami_plot_pen *node;
        struct Screen *scrn = ami_gui_get_screen();
 
        LONG pen = ObtainBestPenA(scrn->ViewPort.ColorMap,
                        (colr & 0x000000ff) << 24,
                        (colr & 0x0000ff00) << 16,
                        (colr & 0x00ff0000) << 8,
                        NULL);
        
        if(pen == -1) NSLOG(netsurf, INFO,
                            "WARNING: Cannot allocate pen for ABGR:%lx", colr);
 
        if((shared_pens != NULL) && (pool_pens != NULL)) {
                if((node = (struct ami_plot_pen *)ami_memory_itempool_alloc(pool_pens, sizeof(struct ami_plot_pen)))) {
                        node->pen = pen;
                        AddTail((struct List *)shared_pens, (struct Node *)node);
                }
        } else {
                /* Immediately release the pen if we can't keep track of it. */
                ReleasePen(scrn->ViewPort.ColorMap, pen);
        }
        return pen;
}
 
void ami_plot_release_pens(struct MinList *shared_pens)
{
        struct Screen *scrn = ami_gui_get_screen();
        struct ami_plot_pen *node;
        struct ami_plot_pen *nnode;
 
        if(shared_pens == NULL) return;
        if(IsMinListEmpty(shared_pens)) return;
        node = (struct ami_plot_pen *)GetHead((struct List *)shared_pens);
 
        do {
                nnode = (struct ami_plot_pen *)GetSucc((struct Node *)node);
                ReleasePen(scrn->ViewPort.ColorMap, node->pen);
                Remove((struct Node *)node);
                ami_memory_itempool_free(pool_pens, node, sizeof(struct ami_plot_pen));
        } while((node = nnode));
}
 
static void ami_plot_setapen(struct gui_globals *glob, struct RastPort *rp, ULONG colr)
{
        if(glob->apen == colr) return;
 
#ifdef __amigaos4__
        if(glob->palette_mapped == false) {
                SetRPAttrs(rp, RPTAG_APenColor,
                        ns_color_to_nscss(colr),
                        TAG_DONE);
        } else
#endif
        {
                LONG pen = ami_plot_obtain_pen(glob->shared_pens, colr);
                if((pen != -1) && (pen != glob->apen_num)) SetAPen(rp, pen);
        }
 
        glob->apen = colr;
}
 
static void ami_plot_setopen(struct gui_globals *glob, struct RastPort *rp, ULONG colr)
{
        if(glob->open == colr) return;
 
#ifdef __amigaos4__
        if(glob->palette_mapped == false) {
                SetRPAttrs(rp, RPTAG_OPenColor,
                        ns_color_to_nscss(colr),
                        TAG_DONE);
        } else
#endif
        {
                LONG pen = ami_plot_obtain_pen(glob->shared_pens, colr);
                if((pen != -1) && (pen != glob->open_num)) SetOPen(rp, pen);
        }
 
        glob->open = colr;
}
 
void ami_plot_clear_bbox(struct RastPort *rp, struct IBox *bbox)
{
        if((bbox == NULL) || (rp == NULL)) return;
 
        EraseRect(rp, bbox->Left, bbox->Top,
                bbox->Width + bbox->Left, bbox->Height + bbox->Top);
}
 
 
static void ami_arc_gfxlib(struct RastPort *rp, int x, int y, int radius, int angle1, int angle2)
{
        float angle1_r = (float)(angle1) * (M_PI / 180.0);
        float angle2_r = (float)(angle2) * (M_PI / 180.0);
        float angle, b, c;
        float step = 0.1; //(angle2_r - angle1_r) / ((angle2_r - angle1_r) * (float)radius);
        int x0, y0, x1, y1;
 
        x0 = x;
        y0 = y;
        
        b = angle1_r;
        c = angle2_r;
        
        x1 = (int)(cos(b) * (float)radius);
        y1 = (int)(sin(b) * (float)radius);
        Move(rp, x0 + x1, y0 - y1);
                
        for(angle = (b + step); angle <= c; angle += step) {
                x1 = (int)(cos(angle) * (float)radius);
                y1 = (int)(sin(angle) * (float)radius);
                Draw(rp, x0 + x1, y0 - y1);
        }
}
 
/**
 */
static nserror
ami_bitmap(struct gui_globals *glob, int x, int y, int width, int height, struct bitmap *bitmap)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_bitmap()");
        struct Screen *scrn = ami_gui_get_screen();
        struct BitMap *tbm;
 
        if (!width || !height) {
                return NSERROR_OK;
        }
 
        if (((x + width) < glob->rect.MinX) ||
            ((y + height) < glob->rect.MinY) ||
            (x > glob->rect.MaxX) ||
            (y > glob->rect.MaxY)) {
                return NSERROR_OK;
        }
 
        tbm = ami_bitmap_get_native(bitmap, width, height, glob->palette_mapped, glob->rp->BitMap);
        if (!tbm) {
                return NSERROR_OK;
        }
 
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] ami_bitmap() got native bitmap");
 
#ifdef __amigaos4__
        if (__builtin_expect((GfxBase->LibNode.lib_Version >= 53) &&
                             (glob->palette_mapped == false), 1)) {
                uint32 comptype = COMPOSITE_Src_Over_Dest;
                uint32 compflags = COMPFLAG_IgnoreDestAlpha;
                if(amiga_bitmap_get_opaque(bitmap)) {
                        compflags |= COMPFLAG_SrcAlphaOverride;
                        comptype = COMPOSITE_Src;
                }
 
                CompositeTags(comptype,tbm,glob->rp->BitMap,
                                        COMPTAG_Flags, compflags,
                                        COMPTAG_DestX,glob->rect.MinX,
                                        COMPTAG_DestY,glob->rect.MinY,
                                        COMPTAG_DestWidth,glob->rect.MaxX - glob->rect.MinX + 1,
                                        COMPTAG_DestHeight,glob->rect.MaxY - glob->rect.MinY + 1,
                                        COMPTAG_SrcWidth,width,
                                        COMPTAG_SrcHeight,height,
                                        COMPTAG_OffsetX,x,
                                        COMPTAG_OffsetY,y,
                                        COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
                                        TAG_DONE);
        } else
#endif
        {
                ULONG tag, tag_data, minterm = 0xc0;
                
                if (glob->palette_mapped == false) {
                        tag = BLITA_UseSrcAlpha;
                        tag_data = !amiga_bitmap_get_opaque(bitmap);
                        minterm = 0xc0;
                } else {
                        tag = BLITA_MaskPlane;
                        if ((tag_data = (ULONG)ami_bitmap_get_mask(bitmap, width, height, tbm)))
                                minterm = MINTERM_SRCMASK;
                }
#ifdef __amigaos4__
                BltBitMapTags(BLITA_Width,width,
                                                BLITA_Height,height,
                                                BLITA_Source,tbm,
                                                BLITA_Dest,glob->rp,
                                                BLITA_DestX,x,
                                                BLITA_DestY,y,
                                                BLITA_SrcType,BLITT_BITMAP,
                                                BLITA_DestType,BLITT_RASTPORT,
                                                BLITA_Minterm, minterm,
                                                tag, tag_data,
                                                TAG_DONE);
#else
                if (tag_data) {
                        BltMaskBitMapRastPort(tbm, 0, 0, glob->rp, x, y, width, height, minterm, tag_data);
                } else {
                        BltBitMapRastPort(tbm, 0, 0, glob->rp, x, y, width, height, 0xc0);
                }
#endif
        }
 
        if ((ami_bitmap_is_nativebm(bitmap, tbm) == false)) {
                ami_rtg_freebitmap(tbm);
        }
 
        return NSERROR_OK;
}
 
 
HOOKF(void, ami_bitmap_tile_hook, struct RastPort *, rp, struct BackFillMessage *)
{
        int xf,yf;
        struct bfbitmap *bfbm = (struct bfbitmap *)hook->h_Data;
        struct Screen *scrn = ami_gui_get_screen();
 
        /* tile down and across to extents  (msg->Bounds.MinX)*/
        for (xf = -bfbm->offsetx; xf < msg->Bounds.MaxX; xf += bfbm->width) {
                for (yf = -bfbm->offsety; yf < msg->Bounds.MaxY; yf += bfbm->height) {
#ifdef __amigaos4__
                        if(__builtin_expect((GfxBase->LibNode.lib_Version >= 53) &&
                                (bfbm->palette_mapped == false), 1)) {
                                CompositeTags(COMPOSITE_Src_Over_Dest, bfbm->bm, rp->BitMap,
                                        COMPTAG_Flags, COMPFLAG_IgnoreDestAlpha,
                                        COMPTAG_DestX, msg->Bounds.MinX,
                                        COMPTAG_DestY, msg->Bounds.MinY,
                                        COMPTAG_DestWidth, msg->Bounds.MaxX - msg->Bounds.MinX + 1,
                                        COMPTAG_DestHeight, msg->Bounds.MaxY - msg->Bounds.MinY + 1,
                                        COMPTAG_SrcWidth, bfbm->width,
                                        COMPTAG_SrcHeight, bfbm->height,
                                        COMPTAG_OffsetX, xf,
                                        COMPTAG_OffsetY, yf,
                                        COMPTAG_FriendBitMap, scrn->RastPort.BitMap,
                                        TAG_DONE);
                        } else
#endif
                        {
                                ULONG tag, tag_data, minterm = 0xc0;
                
                                if(bfbm->palette_mapped == false) {
                                        tag = BLITA_UseSrcAlpha;
                                        tag_data = TRUE;
                                        minterm = 0xc0;
                                } else {
                                        tag = BLITA_MaskPlane;
                                        if((tag_data = (ULONG)bfbm->mask))
                                                minterm = MINTERM_SRCMASK;
                                }
#ifdef __amigaos4__
                                BltBitMapTags(BLITA_Width, bfbm->width,
                                        BLITA_Height, bfbm->height,
                                        BLITA_Source, bfbm->bm,
                                        BLITA_Dest, rp,
                                        BLITA_DestX, xf,
                                        BLITA_DestY, yf,
                                        BLITA_SrcType, BLITT_BITMAP,
                                        BLITA_DestType, BLITT_RASTPORT,
                                        BLITA_Minterm, minterm,
                                        tag, tag_data,
                                        TAG_DONE);
#else
                                if(tag_data) {
                                        BltMaskBitMapRastPort(bfbm->bm, 0, 0, rp, xf, yf,
                                                bfbm->width, bfbm->height, minterm, tag_data);
                                } else {
                                        BltBitMapRastPort(bfbm->bm, 0, 0, rp, xf, yf,
                                                bfbm->width, bfbm->height, minterm);
                                }
#endif
                        }                       
                }
        }
}
 
static void ami_bezier(struct bez_point *restrict a, struct bez_point *restrict b,
                                struct bez_point *restrict c, struct bez_point *restrict d,
                                float t, struct bez_point *restrict p) {
    p->x = pow((1 - t), 3) * a->x + 3 * t * pow((1 -t), 2) * b->x + 3 * (1-t) * pow(t, 2)* c->x + pow (t, 3)* d->x;
    p->y = pow((1 - t), 3) * a->y + 3 * t * pow((1 -t), 2) * b->y + 3 * (1-t) * pow(t, 2)* c->y + pow (t, 3)* d->y;
}
 
 
bool ami_plot_screen_is_palettemapped(void)
{
        /* This may not be entirely correct - previously we returned the state of the current BitMap */
        return palette_mapped;
}
 
 
/**
 * \brief Sets a clip rectangle for subsequent plot operations.
 *
 * \param ctx The current redraw context.
 * \param clip The rectangle to limit all subsequent plot
 *              operations within.
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_clip(const struct redraw_context *ctx, const struct rect *clip)
{
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
        struct Region *reg = NULL;
 
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_clip()");
 
        if (glob->rp->Layer) {
                reg = NewRegion();
 
                glob->rect.MinX = clip->x0;
                glob->rect.MinY = clip->y0;
                glob->rect.MaxX = clip->x1-1;
                glob->rect.MaxY = clip->y1-1;
 
                OrRectRegion(reg,&glob->rect);
 
                reg = InstallClipRegion(glob->rp->Layer,reg);
 
                if(reg) {
                        DisposeRegion(reg);
                }
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Plots an arc
 *
 * plot an arc segment around (x,y), anticlockwise from angle1
 *  to angle2. Angles are measured anticlockwise from
 *  horizontal, in degrees.
 *
 * \param ctx The current redraw context.
 * \param style Style controlling the arc plot.
 * \param x The x coordinate of the arc.
 * \param y The y coordinate of the arc.
 * \param radius The radius of the arc.
 * \param angle1 The start angle of the arc.
 * \param angle2 The finish angle of the arc.
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_arc(const struct redraw_context *ctx,
        const plot_style_t *style,
        int x, int y, int radius, int angle1, int angle2)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_arc()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if (angle2 < angle1) {
                angle2 += 360;
        }
 
        ami_plot_setapen(glob, glob->rp, style->fill_colour);
        ami_arc_gfxlib(glob->rp, x, y, radius, angle1, angle2);
 
        return NSERROR_OK;
}
 
 
/**
 * Plots a circle
 *
 * Plot a circle centered on (x,y), which is optionally filled.
 *
 * \param ctx The current redraw context.
 * \param style Style controlling the circle plot.
 * \param x x coordinate of circle centre.
 * \param y y coordinate of circle centre.
 * \param radius circle radius.
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_disc(const struct redraw_context *ctx,
                const plot_style_t *style,
                int x, int y, int radius)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_disc()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if (style->fill_type != PLOT_OP_TYPE_NONE) {
                ami_plot_setapen(glob, glob->rp, style->fill_colour);
                AreaCircle(glob->rp,x,y,radius);
                AreaEnd(glob->rp);
        }
 
        if (style->stroke_type != PLOT_OP_TYPE_NONE) {
                ami_plot_setapen(glob, glob->rp, style->stroke_colour);
                DrawEllipse(glob->rp,x,y,radius,radius);
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Plots a line
 *
 * plot a line from (x0,y0) to (x1,y1). Coordinates are at
 *  centre of line width/thickness.
 *
 * \param ctx The current redraw context.
 * \param style Style controlling the line plot.
 * \param line A rectangle defining the line to be drawn
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_line(const struct redraw_context *ctx,
                const plot_style_t *style,
                const struct rect *line)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_line()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        glob->rp->PenWidth = plot_style_fixed_to_int(style->stroke_width);
        glob->rp->PenHeight = plot_style_fixed_to_int(style->stroke_width);
 
        switch (style->stroke_type) {
                case PLOT_OP_TYPE_SOLID: /**< Solid colour */
                default:
                        glob->rp->LinePtrn = PATT_LINE;
                break;
 
                case PLOT_OP_TYPE_DOT: /**< Doted plot */
                        glob->rp->LinePtrn = PATT_DOT;
                break;
 
                case PLOT_OP_TYPE_DASH: /**< dashed plot */
                        glob->rp->LinePtrn = PATT_DASH;
                break;
        }
 
        ami_plot_setapen(glob, glob->rp, style->stroke_colour);
        Move(glob->rp, line->x0, line->y0);
        Draw(glob->rp, line->x1, line->y1);
 
        glob->rp->PenWidth = 1;
        glob->rp->PenHeight = 1;
        glob->rp->LinePtrn = PATT_LINE;
 
        return NSERROR_OK;
}
 
 
/**
 * Plots a rectangle.
 *
 * The rectangle can be filled an outline or both controlled
 *  by the plot style The line can be solid, dotted or
 *  dashed. Top left corner at (x0,y0) and rectangle has given
 *  width and height.
 *
 * \param ctx The current redraw context.
 * \param style Style controlling the rectangle plot.
 * \param rect A rectangle defining the line to be drawn
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_rectangle(const struct redraw_context *ctx,
                     const plot_style_t *style,
                     const struct rect *rect)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_rectangle()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if (style->fill_type != PLOT_OP_TYPE_NONE) {
                ami_plot_setapen(glob, glob->rp, style->fill_colour);
                RectFill(glob->rp, rect->x0, rect->y0, rect->x1- 1 , rect->y1 - 1);
        }
 
        if (style->stroke_type != PLOT_OP_TYPE_NONE) {
                glob->rp->PenWidth = plot_style_fixed_to_int(style->stroke_width);
                glob->rp->PenHeight = plot_style_fixed_to_int(style->stroke_width);
 
                switch (style->stroke_type) {
                        case PLOT_OP_TYPE_SOLID: /**< Solid colour */
                        default:
                                glob->rp->LinePtrn = PATT_LINE;
                        break;
 
                        case PLOT_OP_TYPE_DOT: /**< Dotted plot */
                                glob->rp->LinePtrn = PATT_DOT;
                        break;
 
                        case PLOT_OP_TYPE_DASH: /**< dashed plot */
                                glob->rp->LinePtrn = PATT_DASH;
                        break;
                }
 
                ami_plot_setapen(glob, glob->rp, style->stroke_colour);
                Move(glob->rp, rect->x0, rect->y0);
                Draw(glob->rp, rect->x1, rect->y0);
                Draw(glob->rp, rect->x1, rect->y1);
                Draw(glob->rp, rect->x0, rect->y1);
                Draw(glob->rp, rect->x0, rect->y0);
 
                glob->rp->PenWidth = 1;
                glob->rp->PenHeight = 1;
                glob->rp->LinePtrn = PATT_LINE;
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Plot a polygon
 *
 * Plots a filled polygon with straight lines between
 * points. The lines around the edge of the ploygon are not
 * plotted. The polygon is filled with the non-zero winding
 * rule.
 *
 * \param ctx The current redraw context.
 * \param style Style controlling the polygon plot.
 * \param p verticies of polygon
 * \param n number of verticies.
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_polygon(const struct redraw_context *ctx,
                   const plot_style_t *style,
                   const int *p,
                   unsigned int n)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_polygon()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        ami_plot_setapen(glob, glob->rp, style->fill_colour);
 
        if (AreaMove(glob->rp,p[0],p[1]) == -1) {
                NSLOG(netsurf, INFO, "AreaMove: vector list full");
        }
 
        for (uint32 k = 1; k < n; k++) {
                if (AreaDraw(glob->rp,p[k*2],p[(k*2)+1]) == -1) {
                        NSLOG(netsurf, INFO, "AreaDraw: vector list full");
                }
        }
 
        if (AreaEnd(glob->rp) == -1) {
                NSLOG(netsurf, INFO, "AreaEnd: error");
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Plots a path.
 *
 * Path plot consisting of cubic Bezier curves. Line and fill colour is
 *  controlled by the plot style.
 *
 * \param ctx The current redraw context.
 * \param pstyle Style controlling the path plot.
 * \param p elements of path
 * \param n nunber of elements on path
 * \param transform A transform to apply to the path.
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_path(const struct redraw_context *ctx,
                const plot_style_t *pstyle,
                const float *p,
                unsigned int n,
                const float transform[6])
{
        unsigned int i;
        struct bez_point start_p = {0, 0}, cur_p = {0, 0}, p_a, p_b, p_c, p_r;
 
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_path()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if (n == 0) {
                return NSERROR_OK;
        }
 
        if (p[0] != PLOTTER_PATH_MOVE) {
                NSLOG(netsurf, INFO, "Path does not start with move");
                return NSERROR_INVALID;
        }
 
        if (pstyle->fill_colour != NS_TRANSPARENT) {
                ami_plot_setapen(glob, glob->rp, pstyle->fill_colour);
                if (pstyle->stroke_colour != NS_TRANSPARENT) {
                        ami_plot_setopen(glob, glob->rp, pstyle->stroke_colour);
                }
        } else {
                if (pstyle->stroke_colour != NS_TRANSPARENT) {
                        ami_plot_setapen(glob, glob->rp, pstyle->stroke_colour);
                } else {
                        return NSERROR_OK; /* wholly transparent */
                }
        }
 
        /* Construct path */
        for (i = 0; i < n; ) {
                if (p[i] == PLOTTER_PATH_MOVE) {
                        if (pstyle->fill_colour != NS_TRANSPARENT) {
                                if (AreaMove(glob->rp, p[i+1], p[i+2]) == -1) {
                                        NSLOG(netsurf, INFO,
                                              "AreaMove: vector list full");
                                }
                        } else {
                                Move(glob->rp, p[i+1], p[i+2]);
                        }
                        /* Keep track for future Bezier curves/closes etc */
                        start_p.x = p[i+1];
                        start_p.y = p[i+2];
                        cur_p.x = start_p.x;
                        cur_p.y = start_p.y;
                        i += 3;
                } else if (p[i] == PLOTTER_PATH_CLOSE) {
                        if (pstyle->fill_colour != NS_TRANSPARENT) {
                                if (AreaEnd(glob->rp) == -1) {
                                        NSLOG(netsurf, INFO, "AreaEnd: error");
                                }
                        } else {
                                Draw(glob->rp, start_p.x, start_p.y);
                        }
                        i++;
                } else if (p[i] == PLOTTER_PATH_LINE) {
                        if (pstyle->fill_colour != NS_TRANSPARENT) {
                                if (AreaDraw(glob->rp, p[i+1], p[i+2]) == -1) {
                                        NSLOG(netsurf, INFO,
                                              "AreaDraw: vector list full");
                                }
                        } else {
                                Draw(glob->rp, p[i+1], p[i+2]);
                        }
                        cur_p.x = p[i+1];
                        cur_p.y = p[i+2];
                        i += 3;
                } else if (p[i] == PLOTTER_PATH_BEZIER) {
                        p_a.x = p[i+1];
                        p_a.y = p[i+2];
                        p_b.x = p[i+3];
                        p_b.y = p[i+4];
                        p_c.x = p[i+5];
                        p_c.y = p[i+6];
 
                        for (float t = 0.0; t <= 1.0; t += 0.1) {
                                ami_bezier(&cur_p, &p_a, &p_b, &p_c, t, &p_r);
                                if (pstyle->fill_colour != NS_TRANSPARENT) {
                                        if (AreaDraw(glob->rp, p_r.x, p_r.y) == -1) {
                                                NSLOG(netsurf, INFO,
                                                      "AreaDraw: vector list full");
                                        }
                                } else {
                                        Draw(glob->rp, p_r.x, p_r.y);
                                }
                        }
                        cur_p.x = p_c.x;
                        cur_p.y = p_c.y;
                        i += 7;
                } else {
                        NSLOG(netsurf, INFO, "bad path command %f", p[i]);
                        /* End path for safety if using Area commands */
                        if (pstyle->fill_colour != NS_TRANSPARENT) {
                                AreaEnd(glob->rp);
                                BNDRYOFF(glob->rp);
                        }
                        return NSERROR_INVALID;
                }
        }
        if (pstyle->fill_colour != NS_TRANSPARENT) {
                BNDRYOFF(glob->rp);
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Plot a bitmap
 *
 * Tiled plot of a bitmap image. (x,y) gives the top left
 * coordinate of an explicitly placed tile. From this tile the
 * image can repeat in all four directions -- up, down, left
 * and right -- to the extents given by the current clip
 * rectangle.
 *
 * The bitmap_flags say whether to tile in the x and y
 * directions. If not tiling in x or y directions, the single
 * image is plotted. The width and height give the dimensions
 * the image is to be scaled to.
 *
 * \param ctx The current redraw context.
 * \param bitmap The bitmap to plot
 * \param x The x coordinate to plot the bitmap
 * \param y The y coordiante to plot the bitmap
 * \param width The width of area to plot the bitmap into
 * \param height The height of area to plot the bitmap into
 * \param bg the background colour to alpha blend into
 * \param flags the flags controlling the type of plot operation
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_bitmap_tile(const struct redraw_context *ctx,
                struct bitmap *bitmap,
                int x, int y,
                int width,
                int height,
                colour bg,
                bitmap_flags_t flags)
{
        int xf,yf,xm,ym,oy,ox;
        struct BitMap *tbm = NULL;
        struct Hook *bfh = NULL;
        struct bfbitmap bfbm;
        bool repeat_x = (flags & BITMAPF_REPEAT_X);
        bool repeat_y = (flags & BITMAPF_REPEAT_Y);
 
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_bitmap_tile()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if ((width == 0) || (height == 0)) {
                return NSERROR_OK;
        }
 
        if (!(repeat_x || repeat_y)) {
                return ami_bitmap(glob, x, y, width, height, bitmap);
        }
 
        /* If it is a one pixel transparent image, we are wasting our time */
        if ((amiga_bitmap_get_opaque(bitmap) == false) &&
            (bitmap_get_width(bitmap) == 1) &&
            (bitmap_get_height(bitmap) == 1)) {
                return NSERROR_OK;
        }
 
        tbm = ami_bitmap_get_native(bitmap, width, height, glob->palette_mapped, glob->rp->BitMap);
        if (!tbm) {
                return NSERROR_OK;
        }
 
        ox = x;
        oy = y;
 
        /* get left most tile position */
        for (; ox > 0; ox -= width)
 
        /* get top most tile position */
        for (; oy > 0; oy -= height);
 
        if (ox < 0) {
                ox = -ox;
        }
        if (oy < 0) {
                oy = -oy;
        }
        if (repeat_x) {
                xf = glob->rect.MaxX;
                xm = glob->rect.MinX;
        } else {
                xf = x + width;
                xm = x;
        }
 
        if (repeat_y) {
                yf = glob->rect.MaxY;
                ym = glob->rect.MinY;
        } else {
                yf = y + height;
                ym = y;
        }
#ifdef __amigaos4__
        if(amiga_bitmap_get_opaque(bitmap)) {
                bfh = CreateBackFillHook(BFHA_BitMap,tbm,
                                                        BFHA_Width,width,
                                                        BFHA_Height,height,
                                                        BFHA_OffsetX,ox,
                                                        BFHA_OffsetY,oy,
                                                        TAG_DONE);
        } else
#endif
        {
                bfbm.bm = tbm;
                bfbm.width = width;
                bfbm.height = height;
                bfbm.offsetx = ox;
                bfbm.offsety = oy;
                bfbm.mask = ami_bitmap_get_mask(bitmap, width, height, tbm);
                bfbm.palette_mapped = glob->palette_mapped;
                bfh = calloc(1, sizeof(struct Hook));
                bfh->h_Entry = (HOOKFUNC)ami_bitmap_tile_hook;
                bfh->h_SubEntry = 0;
                bfh->h_Data = &bfbm;
        }
 
        InstallLayerHook(glob->rp->Layer,bfh);
        EraseRect(glob->rp,xm,ym,xf,yf);
        InstallLayerHook(glob->rp->Layer,LAYERS_NOBACKFILL);
 
#ifdef __amigaos4__
        if (amiga_bitmap_get_opaque(bitmap)) {
                DeleteBackFillHook(bfh);
        } else
#endif
                free(bfh);
 
        if ((ami_bitmap_is_nativebm(bitmap, tbm) == false)) {
                /**\todo is this logic logical? */
                ami_rtg_freebitmap(tbm);
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Text plotting.
 *
 * \param ctx The current redraw context.
 * \param fstyle plot style for this text
 * \param x x coordinate
 * \param y y coordinate
 * \param text UTF-8 string to plot
 * \param length length of string, in bytes
 * \return NSERROR_OK on success else error code.
 */
static nserror
ami_text(const struct redraw_context *ctx,
                const struct plot_font_style *fstyle,
                int x,
                int y,
                const char *text,
                size_t length)
{
        NSLOG(plot, DEEPDEBUG, "[ami_plotter] Entered ami_text()");
 
        struct gui_globals *glob = (struct gui_globals *)ctx->priv;
 
        if (__builtin_expect(ami_nsfont == NULL, 0)) {
                return NSERROR_OK;
        }
        ami_plot_setapen(glob, glob->rp, fstyle->foreground);
        ami_nsfont->text(glob->rp, text, length, fstyle, x, y, nsoption_bool(font_antialiasing));
 
        return NSERROR_OK;
}
 
 
const struct plotter_table amiplot = {
        .rectangle = ami_rectangle,
        .line = ami_line,
        .polygon = ami_polygon,
        .clip = ami_clip,
        .text = ami_text,
        .disc = ami_disc,
        .arc = ami_arc,
        .bitmap = ami_bitmap_tile,
        .path = ami_path,
        .option_knockout = true,
};