Files
Terminal.Gui/Terminal.Gui/Core/TextFormatter.cs
Charlie Kindel a0522be496 tweaks
2020-06-30 07:22:20 -07:00

599 lines
18 KiB
C#

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using NStack;
namespace Terminal.Gui {
/// <summary>
/// Text alignment enumeration, controls how text is displayed.
/// </summary>
public enum TextAlignment {
/// <summary>
/// Aligns the text to the left of the frame.
/// </summary>
Left,
/// <summary>
/// Aligns the text to the right side of the frame.
/// </summary>
Right,
/// <summary>
/// Centers the text in the frame.
/// </summary>
Centered,
/// <summary>
/// Shows the text as justified text in the frame.
/// </summary>
Justified
}
/// <summary>
/// Provides text formatting capabilites for console apps. Supports, hotkeys, horizontal alignment, multille lines, and word-based line wrap.
/// </summary>
public class TextFormatter {
List<ustring> lines = new List<ustring> ();
ustring text;
TextAlignment textAlignment;
Attribute textColor = -1;
bool needsFormat;
Key hotKey;
Size size;
/// <summary>
/// The text to be displayed. This text is never modified.
/// </summary>
public virtual ustring Text {
get => text;
set {
text = value;
if (Size.IsEmpty) {
// Proivde a default size (width = length of longest line, height = 1)
// TODO: It might makem more sense for the default to be width = length of first line?
Size = new Size (TextFormatter.MaxWidth (Text, int.MaxValue), 1);
}
NeedsFormat = true;
}
}
// TODO: Add Vertical Text Alignment
/// <summary>
/// Controls the horizontal text-alignment property.
/// </summary>
/// <value>The text alignment.</value>
public TextAlignment Alignment {
get => textAlignment;
set {
textAlignment = value;
NeedsFormat = true;
}
}
/// <summary>
/// Gets or sets the size of the area the text will be constrainted to when formatted.
/// </summary>
public Size Size {
get => size;
set {
size = value;
NeedsFormat = true;
}
}
/// <summary>
/// The specifier character for the hotkey (e.g. '_'). Set to '\xffff' to disable hotkey support for this View instance. The default is '\xffff'.
/// </summary>
public Rune HotKeySpecifier { get; set; } = (Rune)0xFFFF;
/// <summary>
/// The position in the text of the hotkey. The hotkey will be rendered using the hot color.
/// </summary>
public int HotKeyPos { get => hotKeyPos; set => hotKeyPos = value; }
/// <summary>
/// Gets the hotkey. Will be an upper case letter or digit.
/// </summary>
public Key HotKey { get => hotKey; internal set => hotKey = value; }
/// <summary>
/// Specifies the mask to apply to the hotkey to tag it as the hotkey. The default value of <c>0x100000</c> causes
/// the underlying Rune to be identified as a "private use" Unicode character.
/// </summary>HotKeyTagMask
public uint HotKeyTagMask { get; set; } = 0x100000;
/// <summary>
/// Gets the formatted lines.
/// </summary>
/// <remarks>
/// <para>
/// Upon a 'get' of this property, if the text needs to be formatted (if <see cref="NeedsFormat"/> is <c>true</c>)
/// <see cref="Format(ustring, int, TextAlignment, bool)"/> will be called internally.
/// </para>
/// </remarks>
public List<ustring> Lines {
get {
// With this check, we protect against subclasses with overrides of Text
if (ustring.IsNullOrEmpty (Text)) {
lines = new List<ustring> ();
lines.Add (ustring.Empty);
NeedsFormat = false;
return lines;
}
if (NeedsFormat) {
var shown_text = text;
if (FindHotKey (text, HotKeySpecifier, true, out hotKeyPos, out hotKey)) {
shown_text = RemoveHotKeySpecifier (Text, hotKeyPos, HotKeySpecifier);
shown_text = ReplaceHotKeyWithTag (shown_text, hotKeyPos);
}
if (Size.IsEmpty) {
throw new InvalidOperationException ("Size must be set before accessing Lines");
}
lines = Format (shown_text, Size.Width, textAlignment, Size.Height > 1);
NeedsFormat = false;
}
return lines;
}
}
/// <summary>
/// Gets or sets whether the <see cref="TextFormatter"/> needs to format the text when <see cref="Draw(Rect, Attribute, Attribute)"/> is called.
/// If it is <c>false</c> when Draw is called, the Draw call will be faster.
/// </summary>
/// <remarks>
/// <para>
/// This is set to true when the properties of <see cref="TextFormatter"/> are set.
/// </para>
/// </remarks>
public bool NeedsFormat { get => needsFormat; set => needsFormat = value; }
static ustring StripCRLF (ustring str)
{
var runes = str.ToRuneList ();
for (int i = 0; i < runes.Count; i++) {
switch (runes [i]) {
case '\n':
runes.RemoveAt (i);
break;
case '\r':
if ((i + 1) < runes.Count && runes [i + 1] == '\n') {
runes.RemoveAt (i);
runes.RemoveAt (i + 1);
i++;
}
break;
}
}
return ustring.Make (runes);
}
static ustring ReplaceCRLFWithSpace (ustring str)
{
var runes = str.ToRuneList ();
for (int i = 0; i < runes.Count; i++) {
switch (runes [i]) {
case '\n':
runes [i] = (Rune)' ';
break;
case '\r':
if ((i + 1) < runes.Count && runes [i + 1] == '\n') {
runes [i] = (Rune)' ';
runes.RemoveAt (i + 1);
i++;
}
break;
}
}
return ustring.Make (runes); ;
}
/// <summary>
/// Formats the provided text to fit within the width provided using word wrapping.
/// </summary>
/// <param name="text">The text to word warp</param>
/// <param name="width">The width to contrain the text to</param>
/// <returns>Returns a list of word wrapped lines.</returns>
/// <remarks>
/// <para>
/// This method does not do any justification.
/// </para>
/// <para>
/// Newlines ('\n' and '\r\n') sequences are honored, adding the appropriate lines to the output.
/// </para>
/// </remarks>
public static List<ustring> WordWrap (ustring text, int width)
{
if (width < 0) {
throw new ArgumentOutOfRangeException ("Width cannot be negative.");
}
int start = 0, end;
var lines = new List<ustring> ();
if (ustring.IsNullOrEmpty (text)) {
return lines;
}
var runes = StripCRLF (text).ToRuneList ();
while ((end = start + width) < runes.Count) {
while (runes [end] != ' ' && end > start)
end -= 1;
if (end == start)
end = start + width;
lines.Add (ustring.Make (runes.GetRange (start, end - start)).TrimSpace ());
start = end;
}
if (start < text.RuneCount) {
lines.Add (ustring.Make (runes.GetRange (start, runes.Count - start)).TrimSpace ());
}
return lines;
}
/// <summary>
/// Justifies text within a specified width.
/// </summary>
/// <param name="text">The text to justify.</param>
/// <param name="width">If the text length is greater that <c>width</c> it will be clipped.</param>
/// <param name="talign">Alignment.</param>
/// <returns>Justified and clipped text.</returns>
public static ustring ClipAndJustify (ustring text, int width, TextAlignment talign)
{
if (width < 0) {
throw new ArgumentOutOfRangeException ("Width cannot be negative.");
}
if (ustring.IsNullOrEmpty (text)) {
return text;
}
var runes = text.ToRuneList ();
int slen = runes.Count;
if (slen > width) {
return ustring.Make (runes.GetRange (0, width));
} else {
if (talign == TextAlignment.Justified) {
return Justify (text, width);
}
return text;
}
}
/// <summary>
/// Justifies the text to fill the width provided. Space will be added between words (demarked by spaces and tabs) to
/// make the text just fit <c>width</c>. Spaces will not be added to the ends.
/// </summary>
/// <param name="text"></param>
/// <param name="width"></param>
/// <param name="spaceChar">Character to replace whitespace and pad with. For debugging purposes.</param>
/// <returns>The justifed text.</returns>
public static ustring Justify (ustring text, int width, char spaceChar = ' ')
{
if (width < 0) {
throw new ArgumentOutOfRangeException ("Width cannot be negative.");
}
if (ustring.IsNullOrEmpty (text)) {
return text;
}
// TODO: Use ustring
var words = text.Split (ustring.Make (' '));// whitespace, StringSplitOptions.RemoveEmptyEntries);
int textCount = words.Sum (arg => arg.RuneCount);
var spaces = words.Length > 1 ? (width - textCount) / (words.Length - 1) : 0;
var extras = words.Length > 1 ? (width - textCount) % words.Length : 0;
var s = new System.Text.StringBuilder ();
//s.Append ($"tc={textCount} sp={spaces},x={extras} - ");
for (int w = 0; w < words.Length; w++) {
var x = words [w];
s.Append (x);
if (w + 1 < words.Length)
for (int i = 0; i < spaces; i++)
s.Append (spaceChar);
if (extras > 0) {
//s.Append ('_');
extras--;
}
}
return ustring.Make (s.ToString ());
}
static char [] whitespace = new char [] { ' ', '\t' };
private int hotKeyPos;
/// <summary>
/// Reformats text into lines, applying text alignment and optionally wrapping text to new lines on word boundaries.
/// </summary>
/// <param name="text"></param>
/// <param name="width">The width to bound the text to for word wrapping and clipping.</param>
/// <param name="talign">Specifies how the text will be aligned horizontally.</param>
/// <param name="wordWrap">If <c>true</c>, the text will be wrapped to new lines as need. If <c>false</c>, forces text to fit a single line. Line breaks are converted to spaces. The text will be clipped to <c>width</c></param>
/// <returns>A list of word wrapped lines.</returns>
/// <remarks>
/// <para>
/// An empty <c>text</c> string will result in one empty line.
/// </para>
/// <para>
/// If <c>width</c> is 0, a single, empty line will be returned.
/// </para>
/// <para>
/// If <c>width</c> is int.MaxValue, the text will be formatted to the maximum width possible.
/// </para>
/// </remarks>
public static List<ustring> Format (ustring text, int width, TextAlignment talign, bool wordWrap)
{
if (width < 0) {
throw new ArgumentOutOfRangeException ("width cannot be negative");
}
List<ustring> lineResult = new List<ustring> ();
if (ustring.IsNullOrEmpty (text) || width == 0) {
lineResult.Add (ustring.Empty);
return lineResult;
}
if (wordWrap == false) {
text = ReplaceCRLFWithSpace (text);
lineResult.Add (ClipAndJustify (text, width, talign));
return lineResult;
}
var runes = text.ToRuneList ();
int runeCount = runes.Count;
int lp = 0;
for (int i = 0; i < runeCount; i++) {
Rune c = text [i];
if (c == '\n') {
var wrappedLines = WordWrap (ustring.Make (runes.GetRange (lp, i - lp)), width);
foreach (var line in wrappedLines) {
lineResult.Add (ClipAndJustify (line, width, talign));
}
if (wrappedLines.Count == 0) {
lineResult.Add (ustring.Empty);
}
lp = i + 1;
}
}
foreach (var line in WordWrap (ustring.Make (runes.GetRange (lp, runeCount - lp)), width)) {
lineResult.Add (ClipAndJustify (line, width, talign));
}
return lineResult;
}
/// <summary>
/// Computes the number of lines needed to render the specified text given the width.
/// </summary>
/// <returns>Number of lines.</returns>
/// <param name="text">Text, may contain newlines.</param>
/// <param name="width">The minimum width for the text.</param>
public static int MaxLines (ustring text, int width)
{
var result = TextFormatter.Format (text, width, TextAlignment.Left, true);
return result.Count;
}
/// <summary>
/// Computes the maximum width needed to render the text (single line or multple lines) given a minimium width.
/// </summary>
/// <returns>Max width of lines.</returns>
/// <param name="text">Text, may contain newlines.</param>
/// <param name="width">The minimum width for the text.</param>
public static int MaxWidth (ustring text, int width)
{
var result = TextFormatter.Format (text, width, TextAlignment.Left, true);
return result.Max (s => s.RuneCount);
}
/// <summary>
/// Calculates the rectangle requried to hold text, assuming no word wrapping.
/// </summary>
/// <param name="x">The x location of the rectangle</param>
/// <param name="y">The y location of the rectangle</param>
/// <param name="text">The text to measure</param>
/// <returns></returns>
public static Rect CalcRect (int x, int y, ustring text)
{
if (ustring.IsNullOrEmpty (text))
return Rect.Empty;
int mw = 0;
int ml = 1;
int cols = 0;
foreach (var rune in text) {
if (rune == '\n') {
ml++;
if (cols > mw)
mw = cols;
cols = 0;
} else {
if (rune != '\r') {
cols++;
}
}
}
if (cols > mw)
mw = cols;
return new Rect (x, y, mw, ml);
}
/// <summary>
/// Finds the hotkey and its location in text.
/// </summary>
/// <param name="text">The text to look in.</param>
/// <param name="hotKeySpecifier">The hotkey specifier (e.g. '_') to look for.</param>
/// <param name="firstUpperCase">If <c>true</c> the legacy behavior of identifying the first upper case character as the hotkey will be eanbled.
/// Regardless of the value of this parameter, <c>hotKeySpecifier</c> takes precidence.</param>
/// <param name="hotPos">Outputs the Rune index into <c>text</c>.</param>
/// <param name="hotKey">Outputs the hotKey.</param>
/// <returns><c>true</c> if a hotkey was found; <c>false</c> otherwise.</returns>
public static bool FindHotKey (ustring text, Rune hotKeySpecifier, bool firstUpperCase, out int hotPos, out Key hotKey)
{
if (ustring.IsNullOrEmpty (text) || hotKeySpecifier == (Rune)0xFFFF) {
hotPos = -1;
hotKey = Key.Unknown;
return false;
}
Rune hot_key = (Rune)0;
int hot_pos = -1;
// Use first hot_key char passed into 'hotKey'.
// TODO: Ignore hot_key of two are provided
// TODO: Do not support non-alphanumeric chars that can't be typed
int i = 0;
foreach (Rune c in text) {
if ((char)c != 0xFFFD) {
if (c == hotKeySpecifier) {
hot_pos = i;
} else if (hot_pos > -1) {
hot_key = c;
break;
}
}
i++;
}
// Legacy support - use first upper case char if the specifier was not found
if (hot_pos == -1 && firstUpperCase) {
i = 0;
foreach (Rune c in text) {
if ((char)c != 0xFFFD) {
if (Rune.IsUpper (c)) {
hot_key = c;
hot_pos = i;
break;
}
}
i++;
}
}
if (hot_key != (Rune)0 && hot_pos != -1) {
hotPos = hot_pos;
if (hot_key.IsValid && char.IsLetterOrDigit ((char)hot_key)) {
hotKey = (Key)char.ToUpperInvariant ((char)hot_key);
return true;
}
}
hotPos = -1;
hotKey = Key.Unknown;
return false;
}
/// <summary>
/// Replaces the Rune at the index specfiied by the <c>hotPos</c> parameter with a tag identifying
/// it as the hotkey.
/// </summary>
/// <param name="text">The text to tag the hotkey in.</param>
/// <param name="hotPos">The Rune index of the hotkey in <c>text</c>.</param>
/// <returns>The text with the hotkey tagged.</returns>
/// <remarks>
/// The returned string will not render correctly without first un-doing the tag. To undo the tag, search for
/// Runes with a bitmask of <c>otKeyTagMask</c> and remove that bitmask.
/// </remarks>
public ustring ReplaceHotKeyWithTag (ustring text, int hotPos)
{
// Set the high bit
var runes = text.ToRuneList ();
if (Rune.IsLetterOrNumber (runes [hotPos])) {
runes [hotPos] = new Rune ((uint)runes [hotPos] | HotKeyTagMask);
}
return ustring.Make (runes);
}
/// <summary>
/// Removes the hotkey specifier from text.
/// </summary>
/// <param name="text">The text to manipulate.</param>
/// <param name="hotKeySpecifier">The hot-key specifier (e.g. '_') to look for.</param>
/// <param name="hotPos">Returns the postion of the hot-key in the text. -1 if not found.</param>
/// <returns>The input text with the hotkey specifier ('_') removed.</returns>
public static ustring RemoveHotKeySpecifier (ustring text, int hotPos, Rune hotKeySpecifier)
{
if (ustring.IsNullOrEmpty (text)) {
return text;
}
// Scan
ustring start = ustring.Empty;
int i = 0;
foreach (Rune c in text) {
if (c == hotKeySpecifier && i == hotPos) {
i++;
continue;
}
start += ustring.Make (c);
i++;
}
return start;
}
/// <summary>
/// Draws the text held by <see cref="TextFormatter"/> to <see cref="Application.Driver"/> using the colors specified.
/// </summary>
/// <param name="bounds">Specifies the screen-relative location and maximum size for drawing the text.</param>
/// <param name="normalColor">The color to use for all text except the hotkey</param>
/// <param name="hotColor">The color to use to draw the hotkey</param>
public void Draw (Rect bounds, Attribute normalColor, Attribute hotColor)
{
// With this check, we protect against subclasses with overrides of Text (like Button)
if (ustring.IsNullOrEmpty (text)) {
return;
}
Application.Driver?.SetAttribute (normalColor);
// Use "Lines" to ensure a Format (don't use "lines"))
for (int line = 0; line < Lines.Count; line++) {
if (line > bounds.Height)
continue;
var runes = lines [line].ToRunes ();
int x;
switch (textAlignment) {
case TextAlignment.Left:
x = bounds.Left;
break;
case TextAlignment.Justified:
x = bounds.Left;
break;
case TextAlignment.Right:
x = bounds.Right - runes.Length;
break;
case TextAlignment.Centered:
x = bounds.Left + (bounds.Width - runes.Length) / 2;
break;
default:
throw new ArgumentOutOfRangeException ();
}
for (var col = bounds.Left; col < bounds.Left + bounds.Width; col++) {
Application.Driver?.Move (col, bounds.Top + line);
var rune = (Rune)' ';
if (col >= x && col < (x + runes.Length)) {
rune = runes [col - x];
}
if ((rune & HotKeyTagMask) == HotKeyTagMask) {
Application.Driver?.SetAttribute (hotColor);
Application.Driver?.AddRune ((Rune)((uint)rune & ~HotKeyTagMask));
Application.Driver?.SetAttribute (normalColor);
} else {
Application.Driver?.AddRune (rune);
}
}
}
}
}
}