SpriteFont

This is a native Direct3D 11 implementation of a bitmap font renderer, similar to the SpriteFont type from XNA Game Studio 4 (Microsoft.Xna.Framework.Graphics.SpriteFont), plus a command line tool (MakeSpriteFont) for building fonts into bitmap format. It is less fully featured than Direct2D and DirectWrite, but may be useful for those who want something simpler and lighter weight.

UWP on Xbox One supports Direct2D/DirectWrite, but Xbox One XDK does not.

Sprite Font Example

Related tutorial: Drawing text

Header

#include <SpriteFont.h>

Initialization

The SpriteFont class requires a SpriteBatch instance and a .spritefont bitmap file.

std::unique_ptr<SpriteBatch> spriteBatch;
std::unique_ptr<SpriteFont> spriteFont;

spriteBatch = std::make_unique<SpriteBatch>(deviceContext);
spriteFont = std::make_unique<SpriteFont>(device, L"myfile.spritefont");

For exception safety, it is recommended you make use of the C++ RAII pattern and use a std::unique_ptr or std::shared_ptr

You create one SpriteFont instance per font style & point-size you want to use to render with. You can use the same SpriteBatch or use several SpriteBatch instances if desired. Be sure to read the Threading model notes for SpriteBatch.

Simple drawing

spriteBatch->Begin();
spriteFont->DrawString(spriteBatch.get(), L"Hello, world!", XMFLOAT2(x, y));
spriteBatch->End();

The DrawString method has several overloads with parameters controlling color, rotation, origin point, scaling, horizontal or vertical mirroring, and layer depth. These work the same way as the equivalent SpriteBatch::Draw parameters.

Constructors

SpriteFont has three constructors:

Pass a filename string to read a binary file created by MakeSpriteFont
Pass a buffer containing a MakeSpriteFont binary that was already loaded some other way
Pass an array of Glyph structs if you prefer to entirely bypass MakeSpriteFont

There is also a forceSRGB option for working around gamma issues with color fonts that are in the sRGB or similar color space but is not encoded explicitly as an SRGB format.

Helpers

In addition to DrawString with various overloads, SpriteFont includes the following helpers:

MeasureString which returns the size of the given string in pixels.

For example, XMVECTOR result = spriteFont->MeasureString( L"Measure" ); would be the pixel width in XMVectorGetX(result) and the pixel height in XMVectorGetY(result):

MeasureString

The string size is computed from the origin to the rightmost pixel rendered by any character glyph. This has the effect of ignoring 'trailing spaces'.

MeasureDrawBounds which returns a RECT bounding the string.

For example, RECT result = spriteFont->MeasureDrawBounds( L"Measure", XMFLOAT2(0.f, 0.f) ); would return a pixel rectangle as follows:

MeasureDrawBounds

ContainsCharacter tests to see if a given character is defined in the font
FindGlyph can be used to obtain size and other metadata for a character in the font. Note if the character is not defined in the font and there is no default character, this function will throw a C++ exception.
GetSpriteSheet returns a reference to the texture used for the sprite font for custom rendering.

Wide-character vs. UTF-8

SpriteFont works internally with UTF-16LE which is the Visual C++ implementation for wide characters (i.e. wchar_t). In order to support use of UTF-8, there are overloads for DrawString, MeasureString, and MeasureDrawBounds which take a narrow-string char which must be UTF-8. UTF-8 by design matches ASCII for the lower 7-bits, but is not the same as Extended ASSCII or ANSI code page 437.

Default character

If you try to DrawString or call MeasureString with a character that is not included in the font, by default you will get an exception. Use SetDefaultCharacter to specify some other character that will be automatically substituted in place of any that are missing. You can also use GetDefaultCharacter to obtain the current default which is also defined as part of the font.

Special characters

SpriteFont will respect new line characters (\n - ASCII character 10), and ignores carriage returns (\r - ASCII character 13). The distance moved for a new line is defined in the font and can be accessed with GetLineSpacing / SetLineSpacing.

There is no special handling for the bell character (\a - ASCII character 7), backspace (\b - ASCII character 8), horizontal tab (\t - ASCII character 9), vertical tab (ASCII character 11), form feed (\f - ASCII character 12), or escape (ASCII character 27). These are all treated as standard characters and if it is missing from the .spritefont, they will all render as the default character or generate an exception if there is no default character defined.

Localization

This implementation supports sparse fonts, so if you are localizing into languages such as Chinese, Japanese, or Korean, you can build a .spritefont including only the specific characters needed by your program. This is usually a good idea for CJK languages, as a complete CJK character set is too large to fit in a Direct3D texture! If you need full CJK support, DrectWrite would be a better choice if available on your target platform. SpriteFont does not support combining characters or right-to-left (RTL) layout, so it will not work for languages with complex layout requirements such as Arabic or Thai.

ASCII

The default character region for MakeSpriteFont from 32 to 127 covers the standard 7-bit ASCII range. For example, here is a C++ Unicode string for the printable characters (this would be an ASCII string if you remove the L prefix).

L" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`"
L"abcdefghijklmnopqrstuvwxyz{|}~"

Extended ASCII

If you are wanting to render an extended ASCII string with SpriteFont, you need to capture the full set of characters which are not contiguous in Unicode (see MakeSpriteFont for details). You then need to convert your 'extended ASCII' string to Unicode using Code page 437 before calling DrawString.

char ascii[...];
wchar_t unicode[...];
if (!MultiByteToWideChar(437, MB_PRECOMPOSED,
    ascii, length-of-ascii-string,
    unicode, length-of-unicode-string))
{
    // Error
}
spriteFont->DrawString(spriteBatch.get(), unicode, ...)

For example, here is a C++ Unicode string with the full extended ASCII IBM PC character set from 128 to 255:

L"\x00C7\x00FC\x00E9\x00E2\x00E4\x00E0\x00E5\x00E7\x00EA
\x00EB\x00E8\x00EF\x00EE\x00EC\x00C4\x00C5\x00C9\x00E6\x00C6\x00F4\x00F6\x00F2\x
00FB\x00F9\x00FF\x00D6\x00DC\x00A2\x00A3\x00A5\x20A7\x0192\x00E1\x00ED\x00F3\x00
FA\x00F1\x00D1\x00AA\x00BA\x00BF\x2310\x00AC\x00BD\x00BC\x00A1\x00AB\x00BB\x2591
\x2592\x2593\x2502\x2524\x2561\x2562\x2556\x2555\x2563\x2551\x2557\x255D\x255C\x
255B\x2510\x2514\x2534\x252C\x251C\x2500\x253C\x255E\x255F\x255A\x2554\x2569\x25
66\x2560\x2550\x256C\x2567\x2568\x2564\x2565\x2559\x2558\x2552\x2553\x256B\x256A
\x2518\x250C\x2588\x2584\x258C\x2590\x2580\x03B1\x00DF\x0393\x03C0\x03A3\x03C3\x
00B5\x03C4\x03A6\x0398\x03A9\x03B4\x221E\x03C6\x03B5\x2229\x2261\x00B1\x2265\x22
64\x2320\x2321\x00F7\x2248\x00B0\x2219\x00B7\x221A\x207F\x00B2\x25A0\x00A0"

The Xbox One exclusive apps version of MultiByteToWideChar does not support code page 437. Generally you should avoid using specific codepages and prefer the use of CP_UTF8 for better portability.

Applications

For code for rendering text in a classic-style scrolling console, see TextConsole.

Code for rendering text mixed with the Xbox controller button spritefont, see ControllerFont.

Feature Level Notes

The Sprite Font implementation is compatible with all feature levels. The primary limitation is on the size of the sprite sheet texture which should fit into the limits for known feature levels (i.e. to support all feature levels, it should be no larger than 2048 x 2048; if you target feature level 9.3 or later you can use 4096 x 4096, etc.).

You are of course free to use a larger texture as long as you set your application's minimum supported feature level as appropriate. MakeSpriteFont will emit warnings if your captured font texture exceeds the various feature level size thresholds.

Threading model

Creation is fully asynchronous, so you can instantiate multiple SpriteFont instances at the same time on different threads. Most SpriteFont methods are thread-safe with the exception of SetLineSpacing and SetDefaultCharacter. Be sure to read the Threading model notes for SpriteBatch as well.