I have searched a lot and tried much but I can not find the proper solution.
I wonder is there any approach for determining exact glyph height in specified font?
I mean here when I want to determine the height of DOT glyph I should receive small height but not height with paddings or the font size.
I have found the solution for determining exact glyph width here (I have used the second approach) but it does not work for height.
UPDATE: I need solution for .NET 1.1
It's not that hard to get the character metrics. GDI contains a function GetGlyphOutline that you can call with the GGO_METRICS constant to get the height and width of the smallest enclosing rectangle required to contain the glyph when rendered. I.e, a 10 point glyph for a dot in font Arial will give a rectangle of 1x1 pixels, and for the letter I 95x.14 if the font is 100 points in size.
These are the declaration for the P/Invoke calls:
// the declarations
public struct FIXED
{
public short fract;
public short value;
}
public struct MAT2
{
[MarshalAs(UnmanagedType.Struct)] public FIXED eM11;
[MarshalAs(UnmanagedType.Struct)] public FIXED eM12;
[MarshalAs(UnmanagedType.Struct)] public FIXED eM21;
[MarshalAs(UnmanagedType.Struct)] public FIXED eM22;
}
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public int x;
public int y;
}
[StructLayout(LayoutKind.Sequential)]
public struct POINTFX
{
[MarshalAs(UnmanagedType.Struct)] public FIXED x;
[MarshalAs(UnmanagedType.Struct)] public FIXED y;
}
[StructLayout(LayoutKind.Sequential)]
public struct GLYPHMETRICS
{
public int gmBlackBoxX;
public int gmBlackBoxY;
[MarshalAs(UnmanagedType.Struct)] public POINT gmptGlyphOrigin;
[MarshalAs(UnmanagedType.Struct)] public POINTFX gmptfxGlyphOrigin;
public short gmCellIncX;
public short gmCellIncY;
}
private const int GGO_METRICS = 0;
private const uint GDI_ERROR = 0xFFFFFFFF;
[DllImport("gdi32.dll")]
static extern uint GetGlyphOutline(IntPtr hdc, uint uChar, uint uFormat,
out GLYPHMETRICS lpgm, uint cbBuffer, IntPtr lpvBuffer, ref MAT2 lpmat2);
[DllImport("gdi32.dll", ExactSpelling = true, PreserveSig = true, SetLastError = true)]
static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj);
The actual code, rather trivial, if you don't consider the P/Invoke redundancies. I tested the code, it works (you can adjust for getting the width as well from GLYPHMETRICS).
Note: this is ad-hoc code, in the real world, you should clean up the HDC's and objects with ReleaseHandle and DeleteObject. Thanks to a comment by user2173353 to point this out.
// if you want exact metrics, use a high font size and divide the result
// otherwise, the resulting rectangle is rounded to nearest int
private int GetGlyphHeight(char letter, string fontName, float fontPointSize)
{
// init the font. Probably better to do this outside this function for performance
Font font = new Font(new FontFamily(fontName), fontPointSize);
GLYPHMETRICS metrics;
// identity matrix, required
MAT2 matrix = new MAT2
{
eM11 = {value = 1},
eM12 = {value = 0},
eM21 = {value = 0},
eM22 = {value = 1}
};
// HDC needed, we use a bitmap
using(Bitmap b = new Bitmap(1,1))
using (Graphics g = Graphics.FromImage(b))
{
IntPtr hdc = g.GetHdc();
IntPtr prev = SelectObject(hdc, font.ToHfont());
uint retVal = GetGlyphOutline(
/* handle to DC */ hdc,
/* the char/glyph */ letter,
/* format param */ GGO_METRICS,
/* glyph-metrics */ out metrics,
/* buffer, ignore */ 0,
/* buffer, ignore */ IntPtr.Zero,
/* trans-matrix */ ref matrix);
if(retVal == GDI_ERROR)
{
// something went wrong. Raise your own error here,
// or just silently ignore
return 0;
}
// return the height of the smallest rectangle containing the glyph
return metrics.gmBlackBoxY;
}
}
GDI_ERROR, with no additional info. This is similar to the dreaded "A generic error occurred in GDI+" in GDI+). I'll update the code to reflect this. –
Hoofer GDI_ERROR. Can you be more specific about "some fonts"? Oh, and if the font height is too low, it can be rounded down to zero, in which case you should try a high font height, like 100 points, to begin with. –
Hoofer GetDesignGlyphMetrics that gets you all the relative metrics for an array of character indices. Working from .NET 1.1 with COM can be a pain though. –
Hoofer using{...} around the Graphics object would take care of this. If that is not the case, you are right and at the end of the using-block, a ReleaseHdc and DeleteObject ought to be called. Hmm, thinking a bit more of this: I think it is probably better to use a SafeHandle derivative, instead of IntPtr, which would then automatically take care of cleaning up. I added a warning note to the post with regards to this. –
Hoofer Can you update the question to include what you have tried ?
By dot glyph I assume you mean the punctuation mark detailed here ?
Is this Glyph height displayed on screen or a printed page ?
I managed to modify the first method in the link you posted in order to count the matching vertical pixels, however identifying the largest height of the glyph is fiddly to do unless you are willing to draw character by character, so this wasn't really a general working solution like the article.
In order to have a general working solution would need identify the largest single pixel vertical region of the character / glyph, then count the number of pixels in that region.
I also managed to verify that Graphics.MeasureString, TextRenderer.MeasureText and Graphics.MeasureCharacterRanges all returned the bounding box which gave a number similar to the font height.
The alternative to this is to Glyph.ActualHeight property which gets the rendered height of the framework element. This part of WPF and the related GlyphTypeface and GlyphRun classes. I wasn't able to test them at this time having only Mono.
The steps for getting Glyph.ActualHeight are as follows
Initialise the arguments for GlyphRun
Initialise GlyphRun object
Access relevant Glyph using glyphTypeface.CharacterToGlyphMap[text[n]] or more correctly glyphTypeface.GlyphIndices[n], where glyphTypeface is your GlyphTypeface, which is created from the Typeface object you make in Step 1.
Relevant resources on using them include
Futher references on GDI (What these classes use under the hood is GDI or GDI+) and Fonts in Windows include
Here's a solution involving WPF. We create an intermediate Geometry object in order to retrieve the accurate bounding box of our text. The advantage of this solution is that it does not actually render anything. Even if you don't use WPF for your interface, you may use this piece of code to do your measurements only, assuming the font rendering size would be the same in GDI, or close enough.
var fontFamily = new FontFamily("Arial");
var typeface = new Typeface(fontFamily, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal);
var fontSize = 15;
var formattedText = new FormattedText(
"Hello World",
CultureInfo.CurrentCulture,
FlowDirection.LeftToRight,
typeface,
fontSize,
Brushes.Black);
var textGeometry = formattedText.BuildGeometry(new Point(0, 0));
double x = textGeometry.Bounds.Left;
double y = textGeometry.Bounds.Right;
double width = textGeometry.Bounds.Width;
double height = textGeometry.Bounds.Height;
Here, "Hello world" measurements are about 77 x 11 units. A single dot gives 1.5 x 1.5.
As an alternative solution, still in WPF, you could use GlyphRun and ComputeInkBoundingBox(). It's a bit more complex and won't support automatic font substitution, though. It would look like this:
var glyphRun = new GlyphRun(glyphTypeFace, 0, false, fontSize,
glyphIndexList,
new Point(0, 0),
advanceWidths,
null, null, null, null,
null, null);
Rect glyphInkBox = glyphRun.ComputeInkBoundingBox();
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