// 完毕：
using System;
using System.IO;
using System.Drawing;
using System.Linq;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Drawing;
using GrapeCity.Documents.Imaging;
using GCTEXT = GrapeCity.Documents.Text;
using GCDRAW = GrapeCity.Documents.Drawing;
namespace DsPdfWeb.Demos
{
// This sample demonstrates the effects of different blend modes
// when drawing on a GcPdfGraphics. Note that the current blend mode
// set on an instance of GcGraphics (including GcPdfGraphics)
// affects not only images but all drawing operations.
// In this sample it is demonstrated by rendering the blend mode
// names on the second page.
public class AllBlendModes
{
public int CreatePDF(Stream stream)
{
var doc = new GcPdfDocument();
var page = doc.NewPage();
var g = page.Graphics;
var iorchid = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "orchid.jpg"));
var ispectr = GCDRAW.Image.FromFile(Path.Combine("Resources", "ImagesBis", "spectrum-pastel-500x500.png"));
const int margin = 36;
const int NCOLS = 4;
var w = (int)((page.Size.Width - margin * 2) / NCOLS);
var h = (int)((iorchid.Height * w) / iorchid.Width);
// Text layout for captions:
var tl = g.CreateTextLayout();
tl.DefaultFormat.Font = GCTEXT.Font.FromFile(Path.Combine("Resources", "Fonts", "cour.ttf"));
tl.DefaultFormat.FontSize = 12;
tl.ParagraphAlignment = ParagraphAlignment.Center;
tl.TextAlignment = TextAlignment.Center;
tl.MaxWidth = w;
tl.MaxHeight = h;
tl.MarginTop = h - g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4f;
int row = 0, col, dy;
// Render all blending modes in a grid:
var modes = Enum.GetValues(typeof(BlendMode));
for (int i = 0; i < 2; ++i)
{
row = col = 0;
GCDRAW.Image iback, ifore;
if (i == 0)
{
iback = ispectr;
ifore = iorchid;
var trc1 = Common.Util.AddNote(
"Below are tiles drawn by composing two images (a spectrum and an orchid) using the " +
"different blend modes supported by DsPdf. " +
"First the spectrum image is drawn normally, then it is overlaid by the orchid image " +
"drawn in a supported blend mode. The blend mode name is shown below each tile." +
"\n" +
"Tiles on the second page are composed of the same images but drawn in reverse order: " +
"the orchid is drawn normally, the spectrum is blended with it using the different modes." +
"\n" +
"Note that the current blend mode affects not only images but any drawing on a GcGraphics. " +
"The blend mode names on the 2nd page illustrate this.",
page);
dy = (int)trc1.Bottom;
}
else // i == 1
{
iback = iorchid;
ifore = ispectr;
page = doc.Pages.Add();
g = page.Graphics;
dy = 0;
}
foreach (var mode in modes)
{
var blendMode = (BlendMode)mode;
if (!g.IsBlendModeSupported(blendMode))
continue;
int x = margin + w * col;
int y = margin + h * row + dy;
var r = new RectangleF(x, y, w, h);
g.BlendMode = BlendMode.Normal;
g.DrawImage(iback, r, null, ImageAlign.StretchImage);
g.BlendMode = blendMode;
g.DrawImage(ifore, r, null, ImageAlign.StretchImage);
g.BlendMode = BlendMode.Normal;
// Caption:
tl.Clear();
tl.Append(blendMode.ToString());
tl.PerformLayout(true);
var rc = tl.ContentRectangle;
rc.Offset(x, y);
rc.Inflate(4, 2);
g.FillRectangle(rc, Color.White);
g.DrawTextLayout(tl, new PointF(x, y));
nextRowCol();
}
}
// Text blends:
page = doc.Pages[1];
g = page.Graphics;
var trc = Common.Util.AddNote(
"Below are supported blend mode names rendered into rectangles using the corresponding blend mode. " +
"Each rectangle is first filled by the spectrum image using BlendMode.Normal, " +
"then black and white texts are drawn using the current blend mode, " +
"finally the same spectrum image is drawn using BlendMode.Difference to black out the background. " +
"Names prefixed with 'B:' are drawn in black, " +
"while names prefixed with 'W:' are drawn in white. " +
"Most combinations yield rather colorful results, but for some the results are invisible.",
page,
new RectangleF(margin, margin + h * row + 12, page.Bounds.Width - margin * 2, 0));
var yoff = (int)trc.Bottom + 12;
tl.DefaultFormat.FontBold = true;
tl.DefaultFormat.FontSize = 16;
h = (int)(g.MeasureString("QWERTY", tl.DefaultFormat).Height * 1.4f) * 2;
tl.MaxWidth = w;
tl.MaxHeight = h;
tl.MarginTop = (h - h / 1.4f) / 2;
tl.DefaultFormat.ForeColor = Color.Black;
var tfWhite = new TextFormat(tl.DefaultFormat) { ForeColor = Color.White };
row = col = 0;
foreach (var mode in modes)
{
var blendMode = (BlendMode)mode;
if (!g.IsBlendModeSupported(blendMode))
continue;
int x = margin + w * col;
int y = yoff + h * row;
var r = new RectangleF(x, y, w, h);
// Draw spectrum image normally:
g.BlendMode = BlendMode.Normal;
g.DrawImage(ispectr, r, null, ImageAlign.StretchImage);
// Draw blend mode name using the current blend mode:
tl.Clear();
tl.AppendLine($"B: {blendMode}");
tl.Append($"W: {blendMode}", tfWhite);
tl.PerformLayout(true);
var rc = tl.ContentRectangle;
rc.Offset(x, y);
rc.Inflate(4, 2);
// Current blend mode:
g.BlendMode = blendMode;
g.DrawTextLayout(tl, new PointF(x, y));
// Draw spectrum image again using BlendMode.Difference
// to produce (mostly) colorful text on black background:
g.BlendMode = BlendMode.Difference;
g.DrawImage(ispectr, r, null, ImageAlign.StretchImage);
// Draw a rectangle to mark the current area:
g.BlendMode = BlendMode.Normal;
g.DrawRectangle(r, Color.Gray);
nextRowCol();
}
// Done:
doc.Save(stream);
return doc.Pages.Count;
//
void nextRowCol()
{
if (++col == NCOLS)
{
col = 0;
++row;
}
}
}
}
}