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path: root/src/plot/16bpp.c
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/*
 * Copyright 2009 Vincent Sanders <vince@simtec.co.uk>
 *
 * This file is part of libnsfb, http://www.netsurf-browser.org/
 * Licenced under the MIT License,
 *                http://www.opensource.org/licenses/mit-license.php
 */

#include <stdbool.h>
#include <endian.h>
#include <stdlib.h>

#include "libnsfb.h"
#include "libnsfb_plot.h"
#include "libnsfb_plot_util.h"

#include "nsfb.h"
#include "plot.h"

static inline uint16_t *get_xy_loc(nsfb_t *nsfb, int x, int y)
{
        return (void *)(nsfb->ptr + (y * nsfb->linelen) + (x << 1));
}

static inline nsfb_colour_t pixel_to_colour(uint16_t pixel)
{
        return ((pixel & 0x1F) << 19) |
              ((pixel & 0x7E0) << 5) |
              ((pixel & 0xF800) >> 8);
}

/* convert a colour value to a 16bpp pixel value ready for screen output */
static inline uint16_t colour_to_pixel(nsfb_colour_t c)
{
        return ((c & 0xF8) << 8) | ((c & 0xFC00 ) >> 5) | ((c & 0xF80000) >> 19);
}

#define SIGN(x)  ((x<0) ?  -1  :  ((x>0) ? 1 : 0))


static bool 
line(nsfb_t *nsfb, int linec, nsfb_bbox_t *line, nsfb_plot_pen_t *pen)
{
        int w;
        uint16_t ent;
        uint16_t *pvideo;
        int x, y, i;
        int dx, dy, sdy;
        int dxabs, dyabs;

        ent = colour_to_pixel(pen->stroke_colour);

        for (;linec > 0; linec--) {

                if (line->y0 == line->y1) {
                        /* horizontal line special cased */

                        if (!nsfb_plot_clip_ctx(nsfb, line)) {
                                /* line outside clipping */
                                line++;
                                continue;
                        }

                        pvideo = get_xy_loc(nsfb, line->x0, line->y0);

                        w = line->x1 - line->x0;
                        while (w-- > 0) 
                                *(pvideo + w) = ent;
                
                } else {
                        /* standard bresenham line */
                        if (!nsfb_plot_clip_line_ctx(nsfb, line)) {
                                /* line outside clipping */
                                line++;
                                continue;
                        }

                        /* the horizontal distance of the line */
                        dx = line->x1 - line->x0;
                        dxabs = abs (dx);

                        /* the vertical distance of the line */
                        dy = line->y1 - line->y0;
                        dyabs = abs (dy);

                        sdy = dx ? SIGN(dy) * SIGN(dx) : SIGN(dy);

                        if (dx >= 0)
                                pvideo = get_xy_loc(nsfb, line->x0, line->y0);
                        else
                                pvideo = get_xy_loc(nsfb, line->x1, line->y1);

                        x = dyabs >> 1;
                        y = dxabs >> 1;

                        if (dxabs >= dyabs) {
                                /* the line is more horizontal than vertical */
                                for (i = 0; i < dxabs; i++) {
                                        *pvideo = ent;

                                        pvideo++;
                                        y += dyabs;
                                        if (y >= dxabs) {
                                                y -= dxabs;
                                                pvideo += sdy * (nsfb->linelen>>1);
                                        }
                                }
                        } else {
                                /* the line is more vertical than horizontal */
                                for (i = 0; i < dyabs; i++) {
                                        *pvideo = ent;
                                        pvideo += sdy * (nsfb->linelen >> 1);

                                        x += dxabs;
                                        if (x >= dyabs) {
                                                x -= dyabs;
                                                pvideo++;
                                        }
                                }
                        }

                }
                line++;
        }
        return true;
}



static bool fill(nsfb_t *nsfb, nsfb_bbox_t *rect, nsfb_colour_t c)
{
        int w;
        uint16_t *pvid16;
        uint16_t ent16;
        uint32_t *pvid32;
        uint32_t ent32;
        uint32_t llen;
        uint32_t width;
        uint32_t height;

        if (!nsfb_plot_clip_ctx(nsfb, rect))
                return true; /* fill lies outside current clipping region */

        ent16 = colour_to_pixel(c);
        width = rect->x1 - rect->x0;
        height = rect->y1 - rect->y0;

        pvid16 = get_xy_loc(nsfb, rect->x0, rect->y0);

        if (((rect->x0 & 1) == 0) && ((width & 1) == 0)) {
                /* aligned to 32bit value and width is even */
                width = width >> 1;
                llen = (nsfb->linelen >> 2) - width;
                ent32 = ent16 | (ent16 << 16);
                pvid32 = (uint32_t *)pvid16;

                while (height-- > 0) {
                        w = width;
                        while (w >= 16) {
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                w-=16;
                        }
                        while (w >= 4) {
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                *pvid32++ = ent32; *pvid32++ = ent32;
                                w-=4;
                        }
                        while (w > 0) {
                                *pvid32++ = ent32;
                                w--;
                        }
                        // for (w = width; w > 0; w--) *pvid32++ = ent32;
                        pvid32 += llen;
                }

        } else {
                llen = (nsfb->linelen >> 1) - width;


                while (height-- > 0) {
                        for (w = width; w > 0; w--) *pvid16++ = ent16;
                        pvid16 += llen;
                }
        }
        return true;
}


static bool point(nsfb_t *nsfb, int x, int y, nsfb_colour_t c)
{
        uint16_t *pvideo;

        /* check point lies within clipping region */
        if ((x < nsfb->clip.x0) || 
            (x >= nsfb->clip.x1) ||
            (y < nsfb->clip.y0) ||
            (y >= nsfb->clip.y1)) 
                return true;

        pvideo = get_xy_loc(nsfb, x, y);
                                
        if ((c & 0xFF000000) != 0) {
                if ((c & 0xFF000000) != 0xFF000000) {
                        c = nsfb_plot_ablend(c, pixel_to_colour(*pvideo));
                }

                *pvideo = colour_to_pixel(c);
        }
        return true;
}

static bool
glyph1(nsfb_t *nsfb,
       nsfb_bbox_t *loc,
       const uint8_t *pixel,
       int pitch,
       nsfb_colour_t c)
{
        uint16_t *pvideo;
        int xloop, yloop;
        int xoff, yoff; /* x and y offset into image */
        int x = loc->x0;
        int y = loc->y0;
        int width = loc->x1 - loc->x0;
        int height = loc->y1 - loc->y0;
        uint16_t fgcol;
        const uint8_t *fntd;
        uint8_t row;

        if (!nsfb_plot_clip_ctx(nsfb, loc))
                return true;

        if (height > (loc->y1 - loc->y0))
                height = (loc->y1 - loc->y0);

        if (width > (loc->x1 - loc->x0))
                width = (loc->x1 - loc->x0);

        xoff = loc->x0 - x;
        yoff = loc->y0 - y;

        pvideo = get_xy_loc(nsfb, loc->x0, loc->y0);

        fgcol = colour_to_pixel(c);

        for (yloop = yoff; yloop < height; yloop++) {
                fntd = pixel + (yloop * (pitch>>3)) + (xoff>>3);
                row = (*fntd++) << (xoff & 3);
                for (xloop = xoff; xloop < width ; xloop++) {
                        if (((xloop % 8) == 0) && (xloop != 0)) {
                                row = *fntd++;
                        }

                        if ((row & 0x80) != 0) {
                                *(pvideo + xloop) = fgcol;
                        }
                        row = row << 1;

                }

                pvideo += (nsfb->linelen >> 1);
        }

        return true;
}

static bool
glyph8(nsfb_t *nsfb,
       nsfb_bbox_t *loc,
       const uint8_t *pixel,
       int pitch,
       nsfb_colour_t c)
{
        uint16_t *pvideo;
        nsfb_colour_t abpixel; /* alphablended pixel */
        int xloop, yloop;
        int xoff, yoff; /* x and y offset into image */
        int x = loc->x0;
        int y = loc->y0;
        int width = loc->x1 - loc->x0;
        int height = loc->y1 - loc->y0;
        uint16_t fgcol;

        if (!nsfb_plot_clip_ctx(nsfb, loc))
                return true;

        if (height > (loc->y1 - loc->y0))
                height = (loc->y1 - loc->y0);

        if (width > (loc->x1 - loc->x0))
                width = (loc->x1 - loc->x0);

        xoff = loc->x0 - x;
        yoff = loc->y0 - y;

        pvideo = get_xy_loc(nsfb, loc->x0, loc->y0);

        fgcol = c & 0xFFFFFF;

        for (yloop = 0; yloop < height; yloop++) {
                for (xloop = 0; xloop < width; xloop++) {
                        abpixel = (pixel[((yoff + yloop) * pitch) + xloop + xoff] << 24) | fgcol;
                        if ((abpixel & 0xFF000000) != 0) {
                                /* pixel is not transparent */
                                if ((abpixel & 0xFF000000) != 0xFF000000) {
                                        abpixel = nsfb_plot_ablend(abpixel,
                                                                   pixel_to_colour(*(pvideo + xloop)));
                                }

                                *(pvideo + xloop) = colour_to_pixel(abpixel);
                        }
                }
                pvideo += (nsfb->linelen >> 1);
        }

        return true;
}

static bool bitmap_scaled(nsfb_t *nsfb, const nsfb_bbox_t *loc,
		const nsfb_colour_t *pixel, int bmp_width, int bmp_height,
		int bmp_stride, bool alpha)
{
	uint16_t *pvideo, *pvideo_limit;
	nsfb_colour_t abpixel; /* alphablended pixel */
	int xloop;
	int xoff, yoff, xoffs; /* x and y offsets into image */
	int x = loc->x0;
	int y = loc->y0;
	int width = loc->x1 - loc->x0; /* size to scale to */
	int height = loc->y1 - loc->y0; /* size to scale to */
	int rheight, rwidth; /* post-clipping render area dimensions */
	int dx, dy; /* scale factor (integer part) */
	int dxr, dyr; /* scale factor (remainder) */
	int rx, ry; /* remainder trackers */
	nsfb_bbox_t clipped; /* clipped display */

	/* The part of the scaled image actually displayed is cropped to the
	 * current context.
	 */
	clipped.x0 = x;
	clipped.y0 = y;
	clipped.x1 = x + width;
	clipped.y1 = y + height;

	if (!nsfb_plot_clip_ctx(nsfb, &clipped))
		return true;

	/* get height of rendering region, after clipping */
	if (height > (clipped.y1 - clipped.y0))
		rheight = (clipped.y1 - clipped.y0);
	else
		rheight = height;

	/* get width of rendering region, after clipping */
	if (width > (clipped.x1 - clipped.x0))
		rwidth = (clipped.x1 - clipped.x0);
	else
		rwidth = width;

	/* start offsets to part of image being scaled, after clipping */
	xoffs = ((clipped.x0 - x) * bmp_width) / width;
	yoff = (((clipped.y0 - y) * bmp_height) / height) * bmp_stride;

	/* get veritcal (y) and horizontal (x) scale factors; both integer
	 * part and remainder */
	dx = bmp_width / width;
	dy = bmp_height / height;
	dxr = bmp_width % width;
	dyr = bmp_height % height;
	rx = ry = 0; /* initialise remainder counters */

	/* plot the image */
	pvideo = get_xy_loc(nsfb, clipped.x0, clipped.y0);
	pvideo_limit = pvideo + (nsfb->linelen >> 2) * rheight;
	if (alpha) {
		for (; pvideo < pvideo_limit; pvideo += (nsfb->linelen >> 1)) {
			/* looping through render area vertically */
			xoff = xoffs;
			rx = 0;
			for (xloop = 0; xloop < rwidth; xloop++) {
				/* looping through render area horizontally */
				/* get value of source pixel in question */
				abpixel = pixel[yoff + xoff];
				if ((abpixel & 0xFF000000) != 0) {
					/* pixel is not transparent; have to
					 * plot something */
					if ((abpixel & 0xFF000000) !=
							0xFF000000) {
						/* pixel is not opaque; need to
						 * blend */
						abpixel = nsfb_plot_ablend(
								abpixel,
								pixel_to_colour(
								*(pvideo +
								xloop)));
					}
					/* plot pixel */
					*(pvideo + xloop) = colour_to_pixel(
							abpixel);
				}
				/* handle horizontal interpolation */
				xoff += dx;
				rx += dxr;
				if (rx >= width) {
					xoff++;
					rx -= width;
				}
			}
			/* handle vertical interpolation */
			yoff += bmp_stride * dy;
			ry += dyr;
			if (ry >= height) {
				yoff += bmp_stride;
				ry -= height;
			}
		}
	} else {
		for (; pvideo < pvideo_limit; pvideo += (nsfb->linelen >> 1)) {
			/* looping through render area vertically */
			xoff = xoffs;
			rx = 0;
			for (xloop = 0; xloop < rwidth; xloop++) {
				/* looping through render area horizontally */
				/* get value of source pixel in question */
				abpixel = pixel[yoff + xoff];
				/* plot pixel */
				*(pvideo + xloop) = colour_to_pixel(abpixel);

				/* handle horizontal interpolation */
				xoff += dx;
				rx += dxr;
				if (rx >= width) {
					xoff++;
					rx -= width;
				}
			}
			/* handle vertical interpolation */
			yoff += bmp_stride * dy;
			ry += dyr;
			if (ry >= height) {
				yoff += bmp_stride;
				ry -= height;
			}
		}
	}
	return true;
}

static bool 
bitmap(nsfb_t *nsfb,
       const nsfb_bbox_t *loc,
       const nsfb_colour_t *pixel, 
       int bmp_width, 
       int bmp_height, 
       int bmp_stride,
       bool alpha)
{
        uint16_t *pvideo;
        nsfb_colour_t abpixel; /* alphablended pixel */
        int xloop, yloop;
        int xoff, yoff; /* x and y offset into image */
        int x = loc->x0;
        int y = loc->y0;
        int width = loc->x1 - loc->x0;
        int height = loc->y1 - loc->y0;
        nsfb_bbox_t clipped; /* clipped display */

        /* Scaled bitmaps are handled by a separate function */
        if (width != bmp_width || height != bmp_height)
                return bitmap_scaled(nsfb, loc, pixel, bmp_width, bmp_height,
                                bmp_stride, alpha);

        /* The part of the scaled image actually displayed is cropped to the
         * current context.
         */
        clipped.x0 = x;
        clipped.y0 = y;
        clipped.x1 = x + width;
        clipped.y1 = y + height;

        if (!nsfb_plot_clip_ctx(nsfb, &clipped))
                return true;

        if (height > (clipped.y1 - clipped.y0))
                height = (clipped.y1 - clipped.y0);

        if (width > (clipped.x1 - clipped.x0))
                width = (clipped.x1 - clipped.x0);

        xoff = clipped.x0 - x;
        yoff = (clipped.y0 - y) * bmp_stride;
        height = height * bmp_stride + yoff;

        /* plot the image */
        pvideo = get_xy_loc(nsfb, clipped.x0, clipped.y0);

        if (alpha) {
                for (yloop = yoff; yloop < height; yloop += bmp_stride) {
                        for (xloop = 0; xloop < width; xloop++) {
                                abpixel = pixel[yloop + xloop + xoff];
                                if ((abpixel & 0xFF000000) != 0) {
                                	/* pixel is not transparent; have to
                                	 * plot something */
                                        if ((abpixel & 0xFF000000) != 0xFF000000) {
                                        	/* pixel is not opaque; need to
                                        	 * blend */
                                                abpixel = nsfb_plot_ablend(abpixel,
                                                                           pixel_to_colour(*(pvideo + xloop)));
                                        }

                                        *(pvideo + xloop) = colour_to_pixel(abpixel);
                                }
                        }
                        pvideo += (nsfb->linelen >> 1);
                }
        } else {
                for (yloop = yoff; yloop < height; yloop += bmp_stride) {
                        for (xloop = 0; xloop < width; xloop++) {
                                abpixel = pixel[yloop + xloop + xoff];
                                *(pvideo + xloop) = colour_to_pixel(abpixel);
                        }
                        pvideo += (nsfb->linelen >> 1);
                }
        }
        return true;
}


static bool readrect(nsfb_t *nsfb, nsfb_bbox_t *rect, nsfb_colour_t *buffer)
{
        uint16_t *pvideo;
        int xloop, yloop;
        int width;

        if (!nsfb_plot_clip_ctx(nsfb, rect)) {
                return true;
        }

        width = rect->x1 - rect->x0;

        pvideo = get_xy_loc(nsfb, rect->x0, rect->y0);

        for (yloop = rect->y0; yloop < rect->y1; yloop += 1) {
                for (xloop = 0; xloop < width; xloop++) {
                        *buffer = pixel_to_colour(*(pvideo + xloop));
                        buffer++;
                }
                pvideo += (nsfb->linelen >> 1);
        }
        return true;
}


const nsfb_plotter_fns_t _nsfb_16bpp_plotters = {
        .line = line,
        .fill = fill,
        .point = point,
        .bitmap = bitmap,
        .glyph8 = glyph8,
        .glyph1 = glyph1,
        .readrect = readrect,
};

/*
 * Local Variables:
 * c-basic-offset:8
 * End:
 */