/// <summary> /// Gets the background pixmap /// </summary> /// <param name="rect"></param> /// <param name="subSample"></param> /// <param name="gamma"></param> /// <param name="retval"></param> /// <returns></returns> public GPixmap GetBgPixmap(GRect rect, int subsample, double gamma, GPixmap retval) { GPixmap pm = null; int width = (Info == null) ? 0 : Info.Width; int height = (Info == null) ? 0 : Info.Height; if ((width <= 0) || (height <= 0) || (Info == null)) { return(null); } double gamma_correction = 1.0D; if ((gamma > 0.0D) && (Info != null)) { gamma_correction = gamma / Info.Gamma; } if (gamma_correction < 0.10000000000000001D) { gamma_correction = 0.10000000000000001D; } else if (gamma_correction > 10D) { gamma_correction = 10D; } IWPixelMap bgIWPixmap = BackgroundIWPixelMap; if (bgIWPixmap != null) { int w = bgIWPixmap.Width; int h = bgIWPixmap.Height; if ((w == 0) || (h == 0) || (width == 0) || (height == 0)) { return(null); } int red = ComputeRed(width, height, w, h); if ((red < 1) || (red > 12)) { return(null); } if (subsample == red) { pm = bgIWPixmap.GetPixmap(1, rect, retval); } else if (subsample == (2 * red)) { pm = bgIWPixmap.GetPixmap(2, rect, retval); } else if (subsample == (4 * red)) { pm = bgIWPixmap.GetPixmap(4, rect, retval); } else if (subsample == (8 * red)) { pm = bgIWPixmap.GetPixmap(8, rect, retval); } else if ((red * 4) == (subsample * 3)) { GRect xrect = new GRect(); xrect.Right = (int)Math.Floor(rect.Right * 4D / 3D); xrect.Bottom = (int)Math.Floor(rect.Bottom * 4D / 3D); xrect.Left = (int)Math.Ceiling((double)rect.Left * 4D / 3D); xrect.Top = (int)Math.Ceiling((double)rect.Top * 4D / 3D); GRect nrect = new GRect(0, 0, rect.Width, rect.Height); if (xrect.Left > w) { xrect.Left = w; } if (xrect.Top > h) { xrect.Top = h; } GPixmap ipm = bgIWPixmap.GetPixmap(1, xrect, null); pm = (retval != null) ? retval : new GPixmap(); pm.Downsample43(ipm, nrect); } else { int po2 = 16; while ((po2 > 1) && (subsample < (po2 * red))) { po2 >>= 1; } int inw = ((w + po2) - 1) / po2; int inh = ((h + po2) - 1) / po2; int outw = ((width + subsample) - 1) / subsample; int outh = ((height + subsample) - 1) / subsample; PixelMapScaler ps = new PixelMapScaler(inw, inh, outw, outh); ps.SetHorzRatio(red * po2, subsample); ps.SetVertRatio(red * po2, subsample); GRect xrect = ps.GetRequiredRect(rect); GPixmap ipm = bgIWPixmap.GetPixmap(po2, xrect, null); pm = (retval != null) ? retval : new GPixmap(); ps.Scale(xrect, ipm, rect, pm); } if ((pm != null) && (gamma_correction != 1.0D)) { pm.ApplyGammaCorrection(gamma_correction); for (int i = 0; i < 9; i++) { pm.ApplyGammaCorrection(gamma_correction); } } return(pm); } else { return(null); } }