Opentk/Source/Utilities/Graphics/Text/GdiPlusGlyphRasterizer.cs

480 lines
18 KiB
C#

#region License
//
// The Open Toolkit Library License
//
// Copyright (c) 2006 - 2008 the Open Toolkit library, except where noted.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do
// so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
#endregion
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;
using OpenTK.Platform;
namespace OpenTK.Graphics.Text
{
sealed class GdiPlusGlyphRasterizer : IGlyphRasterizer
{
#region Fields
Dictionary<TextBlock, TextExtents> block_cache = new Dictionary<TextBlock, TextExtents>();
System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(new Bitmap(1, 1));
IntPtr[] regions = new IntPtr[GdiPlus.MaxMeasurableCharacterRanges];
CharacterRange[] characterRanges = new CharacterRange[GdiPlus.MaxMeasurableCharacterRanges];
Bitmap glyph_surface;
System.Drawing.Graphics glyph_renderer;
readonly List<RectangleF> measured_glyphs = new List<RectangleF>(256);
readonly ObjectPool<PoolableTextExtents> text_extents_pool = new ObjectPool<PoolableTextExtents>();
// Check the constructor, too, for additional flags.
// Used for measuring text. Can set the leftToRight, rightToLeft, vertical and measure trailing spaces flags.
readonly StringFormat measure_string_format = new StringFormat(StringFormat.GenericDefault);
readonly StringFormat measure_string_format_tight = new StringFormat(StringFormat.GenericTypographic);
// Used for loading glyphs. Only use leftToRight!
readonly StringFormat load_glyph_string_format = new StringFormat(StringFormat.GenericDefault);
readonly StringFormat load_glyph_string_format_tight = new StringFormat(StringFormat.GenericTypographic);
static readonly char[] newline_characters = new char[] { '\n', '\r' };
static readonly SizeF MaximumGraphicsClipSize;
#endregion
#region Constructors
static GdiPlusGlyphRasterizer()
{
using (Bitmap bmp = new Bitmap(1, 1))
using (System.Drawing.Graphics gfx = System.Drawing.Graphics.FromImage(bmp))
{
MaximumGraphicsClipSize = gfx.ClipBounds.Size;
}
}
public GdiPlusGlyphRasterizer()
{
measure_string_format.FormatFlags |= StringFormatFlags.MeasureTrailingSpaces | StringFormatFlags.NoClip;
measure_string_format_tight.FormatFlags |= StringFormatFlags.MeasureTrailingSpaces;
}
#endregion
#region IGlyphRasterizer Members
#region Rasterize
public Bitmap Rasterize(Glyph glyph)
{
return Rasterize(glyph, TextQuality.Default);
}
public Bitmap Rasterize(Glyph glyph, TextQuality quality)
{
EnsureSurfaceSize(ref glyph_surface, ref glyph_renderer, glyph.Font);
SetTextRenderingOptions(glyph_renderer, glyph.Font, quality);
RectangleF r2 = new RectangleF();
glyph_renderer.Clear(Color.Transparent);
glyph_renderer.DrawString(glyph.Character.ToString(), glyph.Font, Brushes.White, Point.Empty, //new Point(glyph_surface.Width, 0),
glyph.Font.Style == FontStyle.Italic ? load_glyph_string_format : load_glyph_string_format_tight);
r2 = FindEdges(glyph_surface, true);
//if ((default_string_format.FormatFlags & StringFormatFlags.DirectionRightToLeft) != 0)
//{
// glyph_renderer.DrawString(glyph.Character.ToString(), glyph.Font, Brushes.White, Point.Empty, //new Point(glyph_surface.Width, 0),
// load_glyph_string_format);//glyph.Font.Style == FontStyle.Italic ? load_glyph_string_format : default_string_format);
// r2 = FindEdges(glyph_surface, true);
//}
//else
//{
// glyph_renderer.DrawString(glyph.Character.ToString(), glyph.Font, Brushes.White, Point.Empty,
// load_glyph_string_format_tight); //glyph.Font.Style == FontStyle.Italic ? load_glyph_string_format : default_string_format);
// r2 = FindEdges(glyph_surface, false);
//}
return glyph_surface.Clone(r2, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
}
#endregion
#region MeasureText
public TextExtents MeasureText(TextBlock block)
{
return MeasureText(block, TextQuality.Default);
}
public TextExtents MeasureText(TextBlock block, TextQuality quality)
{
// First, check if we have cached this text block. Do not use block_cache.TryGetValue, to avoid thrashing
// the user's TextBlockExtents struct.
if (block_cache.ContainsKey(block))
return block_cache[block];
// If this block is not cached, we have to measure it and (potentially) place it in the cache.
TextExtents extents = MeasureTextExtents(block, quality);
if ((block.Options & TextPrinterOptions.NoCache) == 0)
block_cache.Add(block, extents);
return extents;
}
#endregion
#region Clear
public void Clear()
{
block_cache.Clear();
}
#endregion
#endregion
#region Private Members
#region EnsureSurfaceSize
void EnsureSurfaceSize(ref Bitmap bmp, ref System.Drawing.Graphics gfx, Font font)
{
if (bmp == null || bmp.Width < 2 * font.Size || bmp.Height < 2 * font.Size)
{
if (bmp != null)
bmp.Dispose();
if (gfx != null)
gfx.Dispose();
bmp = new Bitmap((int)(2 * font.Size), (int)(2 * font.Size));
gfx = System.Drawing.Graphics.FromImage(bmp);
}
}
#endregion
#region SetRenderingOptions
// Modify rendering settings (antialiasing, grid fitting) to improve appearance.
void SetTextRenderingOptions(System.Drawing.Graphics gfx, Font font, TextQuality quality)
{
switch (quality)
{
case TextQuality.Default:
gfx.TextRenderingHint = TextRenderingHint.SystemDefault;
break;
case TextQuality.High:
gfx.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
break;
case TextQuality.Medium:
if (font.Size <= 18.0f)
gfx.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
else
gfx.TextRenderingHint = TextRenderingHint.AntiAlias;
break;
case TextQuality.Low:
if (font.Size <= 18.0f)
gfx.TextRenderingHint = TextRenderingHint.SingleBitPerPixelGridFit;
else
gfx.TextRenderingHint = TextRenderingHint.SingleBitPerPixel;
break;
}
}
#endregion
#region MeasureTextExtents
TextExtents MeasureTextExtents(TextBlock block, TextQuality quality)
{
// Todo: Parse layout options:
StringFormat format = block.Font.Italic ? measure_string_format : measure_string_format_tight;
//StringFormat format = measure_string_format_tight;
if (block.Direction == TextDirection.Vertical)
format.FormatFlags |= StringFormatFlags.DirectionVertical;
else
format.FormatFlags &= ~StringFormatFlags.DirectionVertical;
if (block.Direction == TextDirection.RightToLeft)
format.FormatFlags |= StringFormatFlags.DirectionRightToLeft;
else
format.FormatFlags &= ~StringFormatFlags.DirectionRightToLeft;
if (block.Alignment == TextAlignment.Near)
format.Alignment = StringAlignment.Near;
else if (block.Alignment == TextAlignment.Center)
format.Alignment = StringAlignment.Center;
else
format.Alignment = StringAlignment.Far;
TextExtents extents = text_extents_pool.Acquire();
RectangleF rect = block.Bounds;
// Work around Mono/GDI+ bug, which causes incorrect
// text wraping when block.Bounds == SizeF.Empty.
if (block.Bounds.Size == SizeF.Empty)
rect.Size = MaximumGraphicsClipSize;
SetTextRenderingOptions(graphics, block.Font, quality);
IntPtr native_graphics = GdiPlus.GetNativeGraphics(graphics);
IntPtr native_font = GdiPlus.GetNativeFont(block.Font);
IntPtr native_string_format = GdiPlus.GetNativeStringFormat(format);
float max_width = 0, max_height = 0;
// It seems that the mere presence of \n and \r characters
// is enough for Mono to botch the layout (even if these
// characters are not processed.) We'll need to find a
// different way to perform layout on Mono, probably
// through Pango.
// Todo: This workaround allocates memory.
//if (Configuration.RunningOnMono)
{
string[] lines = block.Text.Replace("\r", String.Empty).Split('\n');
foreach (string s in lines)
{
float width, height;
extents.AddRange(MeasureGlyphExtents(
ref block, s,
native_graphics, native_font, native_string_format,
ref rect, out width, out height));
if ((block.Direction & TextDirection.Vertical) == 0)
rect.Y += block.Font.Height;
else
rect.X += block.Font.Height;
if (width > max_width)
max_width = width;
if (height > max_height)
max_height = height;
}
}
extents.BoundingBox = new RectangleF(extents[0].X, extents[0].Y, max_width, max_height);
return extents;
}
#endregion
#region MeasureGlyphExtents
// Gets the bounds of each character in a line of text.
// Each line is processed in blocks of 32 characters (GdiPlus.MaxMeasurableCharacterRanges).
IEnumerable<RectangleF> MeasureGlyphExtents(
ref TextBlock block, string text,
IntPtr native_graphics, IntPtr native_font, IntPtr native_string_format,
ref RectangleF layoutRect, out float max_width, out float max_height)
{
measured_glyphs.Clear();
max_width = layoutRect.Left;
max_height = layoutRect.Top;
float last_line_width = 0, last_line_height = 0;
int current = 0;
while (current < text.Length)
{
int num_characters = (text.Length - current) > GdiPlus.MaxMeasurableCharacterRanges ?
GdiPlus.MaxMeasurableCharacterRanges :
text.Length - current;
int status = 0;
// Prepare the character ranges and region structs for the measurement.
for (int i = 0; i < num_characters; i++)
{
if (text[current + i] == '\n' || text[current + i] == '\r')
throw new NotSupportedException();
characterRanges[i] = new CharacterRange(current + i, 1);
IntPtr region;
status = GdiPlus.CreateRegion(out region);
regions[i] = region;
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
}
status = GdiPlus.SetStringFormatMeasurableCharacterRanges(native_string_format, num_characters, characterRanges);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
status = GdiPlus.MeasureCharacterRanges(native_graphics, text, text.Length,
native_font, ref layoutRect, native_string_format, num_characters, regions);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
// Read back the results of the measurement.
for (int i = 0; i < num_characters; i++)
{
RectangleF rect = new RectangleF();
GdiPlus.GetRegionBounds(regions[i], native_graphics, ref rect);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
GdiPlus.DeleteRegion(regions[i]);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
if (rect.Bottom > max_height)
max_height = rect.Bottom;
if (rect.Right > max_width)
max_width = rect.Right;
if (rect.X > last_line_width)
last_line_width = rect.X;
if (rect.Y > last_line_height)
last_line_height = rect.Y;
measured_glyphs.Add(rect);
}
current += num_characters;
}
// Make sure the current height is updated, if the the current line has wrapped due to word-wraping.
// Otherwise, the next line will overlap with the current one.
if (measured_glyphs.Count > 1)
{
if ((block.Direction & TextDirection.Vertical) == 0)
{
if (layoutRect.Y < last_line_height)
layoutRect.Y = last_line_height;
}
else
{
if (layoutRect.X < last_line_width)
layoutRect.X = last_line_width;
}
}
return measured_glyphs;
}
#endregion
#region FindEdges
#pragma warning disable 0649
struct Pixel { public byte B, G, R, A; }
#pragma warning restore 0649
// Note: The bool parameter is not used at this point.
// We might need it if we ever load true rightToLeft glyphs.
Rectangle FindEdges(Bitmap bmp, bool rightToLeft)
{
BitmapData data = bmp.LockBits(
new Rectangle(0, 0, bmp.Width, bmp.Height),
ImageLockMode.ReadOnly,
System.Drawing.Imaging.PixelFormat.Format32bppArgb);
//Rectangle rect = rightToLeft ?
// Rectangle.FromLTRB(FindLeftEdge(bmp, data.Scan0), 0, bmp.Width - 1, FindBottomEdge(bmp, data.Scan0)) :
// Rectangle.FromLTRB(0, 0, FindRightEdge(bmp, data.Scan0), FindBottomEdge(bmp, data.Scan0));
Rectangle rect =
Rectangle.FromLTRB(0, 0, FindRightEdge(bmp, data.Scan0), FindBottomEdge(bmp, data.Scan0));
//Rectangle.FromLTRB(FindLeftEdge(bmp, data.Scan0), 0, FindRightEdge(bmp, data.Scan0), FindBottomEdge(bmp, data.Scan0));
bmp.UnlockBits(data);
return rect;
}
#endregion
#region Find[Left|Right|Top|Bottom]Edge
// Iterates through the bmp, and returns the first row or line that contains a non-transparent pixels.
int FindLeftEdge(Bitmap bmp, IntPtr ptr)
{
for (int x = 0; x < bmp.Width; x++)
for (int y = 0; y < bmp.Height; y++)
unsafe
{
if (((Pixel*)(ptr) + y * bmp.Width + x)->A != 0)
return x;
}
return bmp.Width - 1;
}
int FindRightEdge(Bitmap bmp, IntPtr ptr)
{
for (int x = bmp.Width - 1; x >= 0; x--)
for (int y = 0; y < bmp.Height; y++)
unsafe
{
if (((Pixel*)(ptr) + y * bmp.Width + x)->A != 0)
return x + 1;
}
return 0;
}
int FindTopEdge(Bitmap bmp, IntPtr ptr)
{
for (int y = 0; y < bmp.Height; y++)
for (int x = 0; x < bmp.Width; x++)
unsafe
{
if (((Pixel*)(ptr) + y * bmp.Width + x)->A != 0)
return y;
}
return bmp.Height - 1;
}
int FindBottomEdge(Bitmap bmp, IntPtr ptr)
{
for (int y = bmp.Height - 1; y >= 0; y--)
for (int x = 0; x < bmp.Width; x++)
unsafe
{
if (((Pixel*)(ptr) + y * bmp.Width + x)->A != 0)
return y + 1;
}
return 0;
}
#endregion
#endregion
}
}