pixbuf_util.c

Gqview,Linux下基于GTK+库写成的轻量级而能丰富的图像浏览程序。

				{
				dp += d_step;
				}

			sp += s_step;
			}
		}
}

void pixbuf_draw_layout(GdkPixbuf *pixbuf, PangoLayout *layout, GtkWidget *widget,
			gint x, gint y,
			guint8 r, guint8 g, guint8 b, guint8 a)
{
	GdkPixmap *pixmap;
	GdkPixbuf *buffer;
	gint w, h;
	GdkGC *gc;
	gint sx, sy;
	gint dw, dh;

	if (!widget || !widget->window) return;

	pango_layout_get_pixel_size(layout, &w, &h);
	pixmap = gdk_pixmap_new(widget->window, w, h, -1);

	gc = gdk_gc_new(widget->window);
	gdk_gc_copy(gc, widget->style->black_gc);
	gdk_draw_rectangle(pixmap, gc, TRUE, 0, 0, w, h);
	gdk_gc_copy(gc, widget->style->white_gc);
	gdk_draw_layout(pixmap, gc, 0, 0, layout);
	g_object_unref(gc);

	buffer = gdk_pixbuf_new(GDK_COLORSPACE_RGB, FALSE, 8, w, h);
	gdk_pixbuf_get_from_drawable(buffer, pixmap,
				     gdk_drawable_get_colormap(widget->window),
				     0, 0, 0, 0, w, h);
	g_object_unref(pixmap);

	sx = 0;
	sy = 0;
	dw = gdk_pixbuf_get_width(pixbuf);
	dh = gdk_pixbuf_get_height(pixbuf);

	if (x < 0)
		{
		w += x;
		sx = -x;
		x = 0;
		}

	if (y < 0)
		{
		h += y;
		sy = -y;
		y = 0;
		}

	if (x + w > dw)	w = dw - x;
	if (y + h > dh) h = dh - y;

	pixbuf_copy_font(buffer, sx, sy,
			 pixbuf, x, y, w, h,
			 r, g, b, a);

	g_object_unref(buffer);
}

/*
 *-----------------------------------------------------------------------------
 * pixbuf drawing (triangle)
 *-----------------------------------------------------------------------------
 */

void util_clip_triangle(gint x1, gint y1, gint x2, gint y2, gint x3, gint y3,
			gint *rx, gint *ry, gint *rw, gint *rh)
{
	gint tx, ty, tw, th;

	tx = MIN(x1, x2);
	tx = MIN(tx, x3);
	ty = MIN(y1, y2);
	ty = MIN(ty, y3);
	tw = MAX(abs(x1 - x2), abs(x2 - x3));
	tw = MAX(tw, abs(x3 - x1));
	th = MAX(abs(y1 - y2), abs(y2 - y3));
	th = MAX(th, abs(y3 - y1));

	*rx = tx;
	*ry = ty;
	*rw = tw;
	*rh = th;
}

void pixbuf_draw_triangle(GdkPixbuf *pb,
			  gint clip_x, gint clip_y, gint clip_w, gint clip_h,
			  gint x1, gint y1, gint x2, gint y2, gint x3, gint y3,
			  guint8 r, guint8 g, guint8 b, guint8 a)
{
	gint p_alpha;
	gint pw, ph, prs;
	gint rx, ry, rw, rh;
	gint tx, ty, tw, th;
	gint fx1, fy1;
	gint fx2, fy2;
	gint fw, fh;
	guchar *p_pix;
	guchar *pp;
	gint p_step;
	gdouble slope1, slope2;
	gint slope1_x, slope1_y;
	gint y;
	gint t;
	gint middle = FALSE;

	if (!pb) return;

	pw = gdk_pixbuf_get_width(pb);
	ph = gdk_pixbuf_get_height(pb);

	if (!util_clip_region(0, 0, pw, ph,
			      clip_x, clip_y, clip_w, clip_h,
			      &rx, &ry, &rw, &rh)) return;

	util_clip_triangle(x1, y1, x2, y2, x3, y3,
			   &tx, &ty, &tw, &th);

	if (!util_clip_region(rx, ry, rw, rh,
			      tx, ty, tw, th,
			      &fx1, &fy1, &fw, &fh)) return;
	fx2 = fx1 + fw;
	fy2 = fy1 + fh;

	p_alpha = gdk_pixbuf_get_has_alpha(pb);
	prs = gdk_pixbuf_get_rowstride(pb);
	p_pix = gdk_pixbuf_get_pixels(pb);

	p_step = (p_alpha) ? 4 : 3;

	if (y1 > y2)
		{
		t = x1; x1 = x2; x2 = t;
		t = y1; y1 = y2; y2 = t;
		}
	if (y2 > y3)
		{
		t = x2; x2 = x3; x3 = t;
		t = y2; y2 = y3; y3 = t;
		}
	if (y1 > y2)
		{
		t = x1; x1 = x2; x2 = t;
		t = y1; y1 = y2; y2 = t;
		}

	slope1 = (gdouble)(y2 - y1);
	if (slope1) slope1 = (gdouble)(x2 - x1) / slope1;
	slope1_x = x1;
	slope1_y = y1;
	slope2 = (gdouble)(y3 - y1);
	if (slope2) slope2 = (gdouble)(x3 - x1) / slope2;

	for (y = fy1; y < fy2; y++)
		{
		gint xa, xb;

		if (!middle && y > y2)
			{
			slope1 = (gdouble)(y3 - y2);
			if (slope1) slope1 = (gdouble)(x3 - x2) / slope1;
			slope1_x = x2;
			slope1_y = y2;

			middle = TRUE;
			}

		xa = slope1_x + ((gdouble)slope1 * (y - slope1_y) + 0.5);
		xb = x1 + ((gdouble)slope2 * (y - y1) + 0.5);

		if (xa > xb)
			{
			t = xa; xa = xb; xb = t;
			}

		xa = CLAMP(xa, fx1, fx2);
		xb = CLAMP(xb, fx1, fx2);

		pp = p_pix + y * prs + xa * p_step;

		while (xa < xb)
			{
			*pp = (r * a + *pp * (256-a)) >> 8;
			pp++;
			*pp = (g * a + *pp * (256-a)) >> 8;
			pp++;
			*pp = (b * a + *pp * (256-a)) >> 8;
			pp++;
			if (p_alpha) pp++;

			xa++;
			}
		}
}

/*
 *-----------------------------------------------------------------------------
 * pixbuf drawing (line)
 *-----------------------------------------------------------------------------
 */

static gint util_clip_line(gdouble clip_x, gdouble clip_y, gdouble clip_w, gdouble clip_h,
			   gdouble x1, gdouble y1, gdouble x2, gdouble y2,
			   gdouble *rx1, gdouble *ry1, gdouble *rx2, gdouble *ry2)
{
	gint flip = FALSE;
	gdouble d;

	if (x1 > x2)
		{
		gdouble t;

		t = x1; x1 = x2; x2 = t;
		t = y1; y1 = y2; y2 = t;
		flip = TRUE;
		}

	if (x2 < clip_x || x1 > clip_x + clip_w) return FALSE;

	if (y1 < y2)
		{
		if (y2 < clip_y || y1 > clip_y + clip_h) return FALSE;
		}
	else
		{
		if (y1 < clip_y || y2 > clip_y + clip_h) return FALSE;
		}

#if 0
	if (x1 >= clip_x && x2 <= clip_x + clip_w)
		{
		if (y1 < y2)
			{
			if (y1 >= clip_y && y2 <= clip_y + clip_h) return TRUE;
			}
		else
			{
			if (y2 >= clip_y && y1 <= clip_y + clip_h) return TRUE;
			}
		}
#endif

	d = x2 - x1;
	if (d > 0.0)
		{
		gdouble slope;

		slope = (y2 - y1) / d;
		if (x1 < clip_x)
			{
			y1 = y1 + slope * (clip_x - x1);
			x1 = clip_x;
			}
		if (x2 > clip_x + clip_w)
			{
			y2 = y2 + slope * (clip_x + clip_w - x2);
			x2 = clip_x + clip_w;
			}
		}

	if (y1 < y2)
		{
		if (y2 < clip_y || y1 > clip_y + clip_h) return FALSE;
		}
	else
		{
		gdouble t;

		if (y1 < clip_y || y2 > clip_y + clip_h) return FALSE;

		t = x1; x1 = x2; x2 = t;
		t = y1; y1 = y2; y2 = t;
		flip = !flip;
		}

	d = y2 - y1;
	if (d > 0.0)
		{
		gdouble slope;

		slope = (x2 - x1) / d;
		if (y1 < clip_y)
			{
			x1 = x1 + slope * (clip_y - y1);
			y1 = clip_y;
			}
		if (y2 > clip_y + clip_h)
			{
			x2 = x2 + slope * (clip_y + clip_h - y2);
			y2 = clip_y + clip_h;
			}
		}

	if (flip)
		{
		*rx1 = x2;
		*ry1 = y2;
		*rx2 = x1;
		*ry2 = y1;
		}
	else
		{
		*rx1 = x1;
		*ry1 = y1;
		*rx2 = x2;
		*ry2 = y2;
		}

	return TRUE;
}

void pixbuf_draw_line(GdkPixbuf *pb,
		      gint clip_x, gint clip_y, gint clip_w, gint clip_h,
		      gint x1, gint y1, gint x2, gint y2,
		      guint8 r, guint8 g, guint8 b, guint8 a)
{
	gint p_alpha;
	gint pw, ph, prs;
	gint rx, ry, rw, rh;
	gdouble rx1, ry1, rx2, ry2;
	guchar *p_pix;
	guchar *pp;
	gint p_step;
	gdouble slope;
	gdouble x, y;
	gint px, py;
	gint cx1, cy1, cx2, cy2;

	if (!pb) return;

	pw = gdk_pixbuf_get_width(pb);
	ph = gdk_pixbuf_get_height(pb);

	if (!util_clip_region(0, 0, pw, ph,
			      clip_x, clip_y, clip_w, clip_h,
			      &rx, &ry, &rw, &rh)) return;
	if (!util_clip_line((gdouble)rx, (gdouble)ry, (gdouble)rw, (gdouble)rh,
			    (gdouble)x1, (gdouble)y1, (gdouble)x2, (gdouble)y2,
			    &rx1, &ry1, &rx2, &ry2)) return;

	cx1 = rx;
	cy1 = ry;
	cx2 = rx + rw;
	cy2 = ry + rh;

	p_alpha = gdk_pixbuf_get_has_alpha(pb);
	prs = gdk_pixbuf_get_rowstride(pb);
	p_pix = gdk_pixbuf_get_pixels(pb);

	p_step = (p_alpha) ? 4 : 3;

	if (fabs(rx2 - rx1) > fabs(ry2 - ry1))
		{
		if (rx1 > rx2)
			{
			gdouble t;
			t = rx1; rx1 = rx2; rx2 = t;
			t = ry1; ry1 = ry2; ry2 = t;
			}

		slope = rx2 - rx1;
		if (slope != 0.0) slope = (ry2 - ry1) / slope;
		for (x = rx1; x < rx2; x += 1.0)
			{
			px = (gint)(x + 0.5);
			py = (gint)(ry1 + (x - rx1) * slope + 0.5);

			if (px >=  cx1 && px < cx2 && py >= cy1 && py < cy2)
				{
				pp = p_pix + py * prs + px * p_step;
				*pp = (r * a + *pp * (256-a)) >> 8;
				pp++;
				*pp = (g * a + *pp * (256-a)) >> 8;
				pp++;
				*pp = (b * a + *pp * (256-a)) >> 8;
				}
			}
		}
	else
		{
		if (ry1 > ry2)
			{
			gdouble t;
			t = rx1; rx1 = rx2; rx2 = t;
			t = ry1; ry1 = ry2; ry2 = t;
			}

		slope = ry2 - ry1;
		if (slope != 0.0) slope = (rx2 - rx1) / slope;
		for (y = ry1; y < ry2; y += 1.0)
			{
			px = (gint)(rx1 + (y - ry1) * slope + 0.5);
			py = (gint)(y + 0.5);

			if (px >=  cx1 && px < cx2 && py >= cy1 && py < cy2)
				{
				pp = p_pix + py * prs + px * p_step;
				*pp = (r * a + *pp * (256-a)) >> 8;
				pp++;
				*pp = (g * a + *pp * (256-a)) >> 8;
				pp++;
				*pp = (b * a + *pp * (256-a)) >> 8;
				}
			}
		}
}

/*
 *-----------------------------------------------------------------------------
 * pixbuf drawing (fades and shadows)
 *-----------------------------------------------------------------------------
 */

static void pixbuf_draw_fade_linear(guchar *p_pix, gint prs, gint p_alpha,
				    gint s, gint vertical, gint border,
			 	    gint x1, gint y1, gint x2, gint y2,
				    guint8 r, guint8 g, guint8 b, guint8 a)
{
	guchar *pp;
	gint p_step;
	guint8 n = a;
	gint i, j;

	p_step = (p_alpha) ? 4 : 3;
	for (j = y1; j < y2; j++)
		{
		pp = p_pix + j * prs + x1 * p_step;
		if (!vertical) n = a - a * abs(j - s) / border;
		for (i = x1; i < x2; i++)
			{
			if (vertical) n = a - a * abs(i - s) / border;
			*pp = (r * n + *pp * (256-n)) >> 8;
			pp++;
			*pp = (g * n + *pp * (256-n)) >> 8;
			pp++;
			*pp = (b * n + *pp * (256-n)) >> 8;
			pp++;
			if (p_alpha) pp++;
			}
		}
}

static void pixbuf_draw_fade_radius(guchar *p_pix, gint prs, gint p_alpha,
				    gint sx, gint sy, gint border,
			 	    gint x1, gint y1, gint x2, gint y2,
				    guint8 r, guint8 g, guint8 b, guint8 a)
{
	guchar *pp;
	gint p_step;
	gint i, j;

	p_step = (p_alpha) ? 4 : 3;
	for (j = y1; j < y2; j++)
		{
		pp = p_pix + j * prs + x1 * p_step;
		for (i = x1; i < x2; i++)
			{
			guint8 n;
			gint r;

			r = MIN(border, (gint)sqrt((i-sx)*(i-sx) + (j-sy)*(j-sy)));
			n = a - a * r / border;
			*pp = (r * n + *pp * (256-n)) >> 8;
			pp++;
			*pp = (g * n + *pp * (256-n)) >> 8;
			pp++;
			*pp = (b * n + *pp * (256-n)) >> 8;
			pp++;
			if (p_alpha) pp++;
			}
		}
}

void pixbuf_draw_shadow(GdkPixbuf *pb,
			gint clip_x, gint clip_y, gint clip_w, gint clip_h,
			gint x, gint y, gint w, gint h, gint border,
			guint8 r, guint8 g, guint8 b, guint8 a)
{
	gint p_alpha;
	gint pw, ph, prs;
	gint rx, ry, rw, rh;
	gint fx, fy, fw, fh;
	guchar *p_pix;

	if (!pb) return;

	pw = gdk_pixbuf_get_width(pb);
	ph = gdk_pixbuf_get_height(pb);

	if (!util_clip_region(0, 0, pw, ph,
			      clip_x, clip_y, clip_w, clip_h,
			      &rx, &ry, &rw, &rh)) return;

	p_alpha = gdk_pixbuf_get_has_alpha(pb);
	prs = gdk_pixbuf_get_rowstride(pb);
	p_pix = gdk_pixbuf_get_pixels(pb);

	if (util_clip_region(x + border, y + border, w - border * 2, h - border * 2,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_rect_fill(pb, fx, fy, fw, fh, r, g, b, a);
		}

	if (border < 1) return;

	if (util_clip_region(x, y + border, border, h - border * 2,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_linear(p_pix, prs, p_alpha,
					x + border, TRUE, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x + w - border, y + border, border, h - border * 2,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_linear(p_pix, prs, p_alpha,
					x + w - border, TRUE, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x + border, y, w - border * 2, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_linear(p_pix, prs, p_alpha,
					y + border, FALSE, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x + border, y + h - border, w - border * 2, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_linear(p_pix, prs, p_alpha,
					y + h - border, FALSE, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x, y, border, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_radius(p_pix, prs, p_alpha,
					x + border, y + border, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x + w - border, y, border, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_radius(p_pix, prs, p_alpha,
					x + w - border, y + border, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x, y + h - border, border, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_radius(p_pix, prs, p_alpha,
					x + border, y + h - border, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
	if (util_clip_region(x + w - border, y + h - border, border, border,
			     rx, ry, rw, rh,
			     &fx, &fy, &fw, &fh))
		{
		pixbuf_draw_fade_radius(p_pix, prs, p_alpha,
					x + w - border, y + h - border, border,
					fx, fy, fx + fw, fy + fh,
					r, g, b, a);
		}
}