scummvm/graphics/font.cpp
Thanasis Antoniou 1bca3de594 COMMON: Support text wrapping with even width line segments
The new arguments are optional. The lines segments will be close to the same width.

The algorithm is similar to the one we had for Blade Runner but not exactly the same, since that one would wrap a line at a white space after the theoretical split point (quotient of full line text width divided by target lines number)
2019-08-02 00:08:38 +02:00

470 lines
15 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "graphics/font.h"
#include "graphics/managed_surface.h"
#include "common/array.h"
#include "common/util.h"
namespace Graphics {
int Font::getKerningOffset(uint32 left, uint32 right) const {
return 0;
}
Common::Rect Font::getBoundingBox(uint32 chr) const {
return Common::Rect(getCharWidth(chr), getFontHeight());
}
namespace {
template<class StringType>
Common::Rect getBoundingBoxImpl(const Font &font, const StringType &str, int x, int y, int w, TextAlign align, int deltax) {
// We follow the logic of drawStringImpl here. The only exception is
// that we do allow an empty width to be specified here. This allows us
// to obtain the complete bounding box of a string.
const int leftX = x, rightX = w ? (x + w) : 0x7FFFFFFF;
int width = font.getStringWidth(str);
if (align == kTextAlignCenter)
x = x + (w - width)/2;
else if (align == kTextAlignRight)
x = x + w - width;
x += deltax;
bool first = true;
Common::Rect bbox;
typename StringType::unsigned_type last = 0;
for (typename StringType::const_iterator i = str.begin(), end = str.end(); i != end; ++i) {
const typename StringType::unsigned_type cur = *i;
x += font.getKerningOffset(last, cur);
last = cur;
Common::Rect charBox = font.getBoundingBox(cur);
if (x + charBox.right > rightX)
break;
if (x + charBox.right >= leftX) {
charBox.translate(x, y);
if (first) {
bbox = charBox;
first = false;
} else {
bbox.extend(charBox);
}
}
x += font.getCharWidth(cur);
}
return bbox;
}
template<class StringType>
int getStringWidthImpl(const Font &font, const StringType &str) {
int space = 0;
typename StringType::unsigned_type last = 0;
for (uint i = 0; i < str.size(); ++i) {
const typename StringType::unsigned_type cur = str[i];
space += font.getCharWidth(cur) + font.getKerningOffset(last, cur);
last = cur;
}
return space;
}
template<class StringType>
void drawStringImpl(const Font &font, Surface *dst, const StringType &str, int x, int y, int w, uint32 color, TextAlign align, int deltax) {
// The logic in getBoundingImpl is the same as we use here. In case we
// ever change something here we will need to change it there too.
assert(dst != 0);
const int leftX = x, rightX = x + w;
int width = font.getStringWidth(str);
if (align == kTextAlignCenter)
x = x + (w - width)/2;
else if (align == kTextAlignRight)
x = x + w - width;
x += deltax;
typename StringType::unsigned_type last = 0;
for (typename StringType::const_iterator i = str.begin(), end = str.end(); i != end; ++i) {
const typename StringType::unsigned_type cur = *i;
x += font.getKerningOffset(last, cur);
last = cur;
Common::Rect charBox = font.getBoundingBox(cur);
if (x + charBox.right > rightX)
break;
if (x + charBox.right >= leftX)
font.drawChar(dst, cur, x, y, color);
x += font.getCharWidth(cur);
}
}
template<class StringType>
struct WordWrapper {
Common::Array<StringType> &lines;
int actualMaxLineWidth;
WordWrapper(Common::Array<StringType> &l) : lines(l), actualMaxLineWidth(0) {
}
void add(StringType &line, int &w) {
if (actualMaxLineWidth < w)
actualMaxLineWidth = w;
lines.push_back(line);
line.clear();
w = 0;
}
void clear() {
lines.clear();
actualMaxLineWidth = 0;
}
};
template<class StringType>
int wordWrapTextImpl(const Font &font, const StringType &str, int maxWidth, Common::Array<StringType> &lines, int initWidth, bool evenWidthLinesModeEnabled, bool wrapOnExplicitNewLines) {
WordWrapper<StringType> wrapper(lines);
StringType line;
StringType tmpStr;
int lineWidth = initWidth;
int tmpWidth = 0;
int fullTextWidthEWL = initWidth; // this replaces new line characters (if any) with single spaces - it is used in Even Width Lines mode
// The rough idea behind this algorithm is as follows:
// We accumulate characters into the string tmpStr. Whenever a full word
// has been gathered together this way, we 'commit' it to the line buffer
// 'line', i.e. we add tmpStr to the end of line, then clear it. Before
// we do that, we check whether it would cause 'line' to exceed maxWidth;
// in that case, we first add line to lines, then reset it.
//
// If a newline character is read, then we also add line to lines and clear it.
//
// Special care has to be taken to account for 'words' that exceed the width
// of a line. If we encounter such a word, we have to wrap it over multiple
// lines.
typename StringType::unsigned_type last = 0;
// When EvenWidthLines mode is enabled then we require an early loop over the entire string
// in order to get the full width of the text
//
// "Wrap On Explicit New Lines" and "Even Width Lines" modes are mutually exclusive,
// If both are set to true and there are new line characters in the text,
// then "Even Width Lines" mode is disabled.
//
if (evenWidthLinesModeEnabled) {
// Early loop to get the full width of the text
for (typename StringType::const_iterator x = str.begin(); x != str.end(); ++x) {
typename StringType::unsigned_type c = *x;
// Check for Windows and Mac line breaks
if (c == '\r') {
if (x != str.end() && *(x + 1) == '\n') {
++x;
}
c = '\n';
}
if (c == '\n') {
if (!wrapOnExplicitNewLines) {
c = ' ';
} else {
evenWidthLinesModeEnabled = false;
break;
}
}
const int w = font.getCharWidth(c) + font.getKerningOffset(last, c);
last = c;
fullTextWidthEWL += w;
}
}
int targetTotalLinesNumberEWL = 0;
int targetMaxLineWidth = 0;
do {
if (evenWidthLinesModeEnabled) {
wrapper.clear();
targetTotalLinesNumberEWL += 1;
// We add +2 to the fullTextWidthEWL to account for possible shadow pixels
// We add +10 * font.getCharWidth(' ') to the quotient since we want to allow some extra margin (about an extra wprd's length)
// since that yields better looking results
targetMaxLineWidth = ((fullTextWidthEWL + 2) / targetTotalLinesNumberEWL) + 10 * font.getCharWidth(' ');
if (targetMaxLineWidth > maxWidth) {
// repeat the loop with increased targetTotalLinesNumberEWL
continue;
}
} else {
targetMaxLineWidth = maxWidth;
}
last = 0;
tmpWidth = 0;
for (typename StringType::const_iterator x = str.begin(); x != str.end(); ++x) {
typename StringType::unsigned_type c = *x;
// Convert Windows and Mac line breaks into plain \n
if (c == '\r') {
if (x != str.end() && *(x + 1) == '\n') {
++x;
}
c = '\n';
}
// if wrapping on explicit new lines is disabled, then new line characters should be treated as a single white space char
if (!wrapOnExplicitNewLines && c == '\n') {
c = ' ';
}
const int currentCharWidth = font.getCharWidth(c);
const int w = currentCharWidth + font.getKerningOffset(last, c);
last = c;
const bool wouldExceedWidth = (lineWidth + tmpWidth + w > targetMaxLineWidth);
// If this char is a whitespace, then it represents a potential
// 'wrap point' where wrapping could take place. Everything that
// came before it can now safely be added to the line, as we know
// that it will not have to be wrapped.
if (Common::isSpace(c)) {
line += tmpStr;
lineWidth += tmpWidth;
tmpStr.clear();
tmpWidth = 0;
// If we encounter a line break (\n), or if the new space would
// cause the line to overflow: start a new line
if ((wrapOnExplicitNewLines && c == '\n') || wouldExceedWidth) {
wrapper.add(line, lineWidth);
continue;
}
}
// If the max line width would be exceeded by adding this char,
// insert a line break.
if (wouldExceedWidth) {
// Commit what we have so far, *if* we have anything.
// If line is empty, then we are looking at a word
// which exceeds the maximum line width.
if (lineWidth > 0) {
wrapper.add(line, lineWidth);
// Trim left side
while (tmpStr.size() && Common::isSpace(tmpStr[0])) {
tmpStr.deleteChar(0);
// This is not very fast, but it is the simplest way to
// assure we do not mess something up because of kerning.
tmpWidth = font.getStringWidth(tmpStr);
}
if (tmpStr.empty()) {
// If tmpStr is empty, we might have removed the space before 'c'.
// That means we have to recompute the kerning.
tmpWidth += currentCharWidth + font.getKerningOffset(0, c);
tmpStr += c;
continue;
}
} else {
wrapper.add(tmpStr, tmpWidth);
}
}
tmpWidth += w;
tmpStr += c;
}
// If some text is left over, add it as the final line
line += tmpStr;
lineWidth += tmpWidth;
if (lineWidth > 0) {
wrapper.add(line, lineWidth);
}
} while (evenWidthLinesModeEnabled
&& (targetMaxLineWidth > maxWidth));
return wrapper.actualMaxLineWidth;
}
} // End of anonymous namespace
Common::Rect Font::getBoundingBox(const Common::String &input, int x, int y, const int w, TextAlign align, int deltax, bool useEllipsis) const {
// In case no width was given we cannot use ellipsis or any alignment
// apart from left alignment.
if (w == 0) {
if (useEllipsis) {
warning("Font::getBoundingBox: Requested ellipsis when no width was specified");
}
if (align != kTextAlignLeft) {
warning("Font::getBoundingBox: Requested text alignment when no width was specified");
}
useEllipsis = false;
align = kTextAlignLeft;
}
const Common::String str = useEllipsis ? handleEllipsis(input, w) : input;
return getBoundingBoxImpl(*this, str, x, y, w, align, deltax);
}
Common::Rect Font::getBoundingBox(const Common::U32String &str, int x, int y, const int w, TextAlign align) const {
// In case no width was given we cannot any alignment apart from left
// alignment.
if (w == 0) {
if (align != kTextAlignLeft) {
warning("Font::getBoundingBox: Requested text alignment when no width was specified");
}
align = kTextAlignLeft;
}
return getBoundingBoxImpl(*this, str, x, y, w, align, 0);
}
int Font::getStringWidth(const Common::String &str) const {
return getStringWidthImpl(*this, str);
}
int Font::getStringWidth(const Common::U32String &str) const {
return getStringWidthImpl(*this, str);
}
void Font::drawChar(ManagedSurface *dst, uint32 chr, int x, int y, uint32 color) const {
drawChar(&dst->_innerSurface, chr, x, y, color);
Common::Rect charBox = getBoundingBox(chr);
charBox.translate(x, y);
dst->addDirtyRect(charBox);
}
void Font::drawString(Surface *dst, const Common::String &str, int x, int y, int w, uint32 color, TextAlign align, int deltax, bool useEllipsis) const {
Common::String renderStr = useEllipsis ? handleEllipsis(str, w) : str;
drawStringImpl(*this, dst, renderStr, x, y, w, color, align, deltax);
}
void Font::drawString(Surface *dst, const Common::U32String &str, int x, int y, int w, uint32 color, TextAlign align, int deltax) const {
drawStringImpl(*this, dst, str, x, y, w, color, align, deltax);
}
void Font::drawString(ManagedSurface *dst, const Common::String &str, int x, int y, int w, uint32 color, TextAlign align, int deltax, bool useEllipsis) const {
drawString(&dst->_innerSurface, str, x, y, w, color, align, deltax, useEllipsis);
if (w != 0) {
dst->addDirtyRect(getBoundingBox(str, x, y, w, align, deltax, useEllipsis));
}
}
void Font::drawString(ManagedSurface *dst, const Common::U32String &str, int x, int y, int w, uint32 color, TextAlign align, int deltax) const {
drawString(&dst->_innerSurface, str, x, y, w, color, align, deltax);
if (w != 0) {
dst->addDirtyRect(getBoundingBox(str, x, y, w, align));
}
}
int Font::wordWrapText(const Common::String &str, int maxWidth, Common::Array<Common::String> &lines, int initWidth, bool evenWidthLinesModeEnabled, bool wrapOnExplicitNewLines) const {
return wordWrapTextImpl(*this, str, maxWidth, lines, initWidth, evenWidthLinesModeEnabled, wrapOnExplicitNewLines);
}
int Font::wordWrapText(const Common::U32String &str, int maxWidth, Common::Array<Common::U32String> &lines, int initWidth, bool evenWidthLinesModeEnabled, bool wrapOnExplicitNewLines) const {
return wordWrapTextImpl(*this, str, maxWidth, lines, initWidth, evenWidthLinesModeEnabled, wrapOnExplicitNewLines);
}
Common::String Font::handleEllipsis(const Common::String &input, int w) const {
Common::String s = input;
int width = getStringWidth(s);
if (width > w && s.hasSuffix("...")) {
// String is too wide. Check whether it ends in an ellipsis
// ("..."). If so, remove that and try again!
s.deleteLastChar();
s.deleteLastChar();
s.deleteLastChar();
width = getStringWidth(s);
}
if (width > w) {
Common::String str;
// String is too wide. So we shorten it "intelligently" by
// replacing parts of the string by an ellipsis. There are
// three possibilities for this: replace the start, the end, or
// the middle of the string. What is best really depends on the
// context; but unless we want to make this configurable,
// replacing the middle seems to be a good compromise.
const int ellipsisWidth = getStringWidth("...");
// SLOW algorithm to remove enough of the middle. But it is good enough
// for now.
const int halfWidth = (w - ellipsisWidth) / 2;
int w2 = 0;
Common::String::unsigned_type last = 0;
uint i = 0;
for (; i < s.size(); ++i) {
const Common::String::unsigned_type cur = s[i];
int charWidth = getCharWidth(cur) + getKerningOffset(last, cur);
if (w2 + charWidth > halfWidth)
break;
last = cur;
w2 += charWidth;
str += cur;
}
// At this point we know that the first 'i' chars are together 'w2'
// pixels wide. We took the first i-1, and add "..." to them.
str += "...";
last = '.';
// The original string is width wide. Of those we already skipped past
// w2 pixels, which means (width - w2) remain.
// The new str is (w2+ellipsisWidth) wide, so we can accommodate about
// (w - (w2+ellipsisWidth)) more pixels.
// Thus we skip ((width - w2) - (w - (w2+ellipsisWidth))) =
// (width + ellipsisWidth - w)
int skip = width + ellipsisWidth - w;
for (; i < s.size() && skip > 0; ++i) {
const Common::String::unsigned_type cur = s[i];
skip -= getCharWidth(cur) + getKerningOffset(last, cur);
last = cur;
}
// Append the remaining chars, if any
for (; i < s.size(); ++i) {
str += s[i];
}
return str;
} else {
return s;
}
}
} // End of namespace Graphics