OSDText.cc

Go to the documentation of this file.

#include "OSDText.hh"
#include "TTFFont.hh"
#include "Display.hh"
#include "CommandException.hh"
#include "FileContext.hh"
#include "FileOperations.hh"
#include "GLImage.hh"
#include "TclObject.hh"
#include "StringOp.hh"
#include "join.hh"
#include "narrow.hh"
#include "stl.hh"
#include "unreachable.hh"
#include "utf8_core.hh"
#include <cassert>
#include <cmath>
#include <memory>
 
using std::string;
using std::string_view;
using namespace gl;
 
namespace openmsx {
 
OSDText::OSDText(Display& display_, const TclObject& name_)
        : OSDImageBasedWidget(display_, name_)
        , fontFile("skins/Vera.ttf.gz")
{
}
 
void OSDText::setProperty(
        Interpreter& interp, string_view propName, const TclObject& value)
{
        if (propName == "-text") {
                string_view val = value.getString();
                if (text != val) {
                        text = val;
                        // note: don't invalidate font (don't reopen font file)
                        OSDImageBasedWidget::invalidateLocal();
                        invalidateChildren();
                }
        } else if (propName == "-font") {
                string val(value.getString());
                if (fontFile != val) {
                        if (string file = systemFileContext().resolve(val);
                            !FileOperations::isRegularFile(file)) {
                                throw CommandException("Not a valid font file: ", val);
                        }
                        fontFile = val;
                        invalidateRecursive();
                }
        } else if (propName == "-size") {
                int size2 = value.getInt(interp);
                if (size != size2) {
                        size = size2;
                        invalidateRecursive();
                }
        } else if (propName == "-wrap") {
                string_view val = value.getString();
                WrapMode wrapMode2 = [&] {
                        if (val == "none") {
                                return NONE;
                        } else if (val == "word") {
                                return WORD;
                        } else if (val == "char") {
                                return CHAR;
                        } else {
                                throw CommandException("Not a valid value for -wrap, "
                                        "expected one of 'none word char', but got '",
                                        val, "'.");
                        }
                }();
                if (wrapMode != wrapMode2) {
                        wrapMode = wrapMode2;
                        invalidateRecursive();
                }
        } else if (propName == "-wrapw") {
                float wrapw2 = value.getFloat(interp);
                if (wrapw != wrapw2) {
                        wrapw = wrapw2;
                        invalidateRecursive();
                }
        } else if (propName == "-wraprelw") {
                float wraprelw2 = value.getFloat(interp);
                if (wraprelw != wraprelw2) {
                        wraprelw = wraprelw2;
                        invalidateRecursive();
                }
        } else {
                OSDImageBasedWidget::setProperty(interp, propName, value);
        }
}
 
void OSDText::getProperty(string_view propName, TclObject& result) const
{
        if (propName == "-text") {
                result = text;
        } else if (propName == "-font") {
                result = fontFile;
        } else if (propName == "-size") {
                result = size;
        } else if (propName == "-wrap") {
                string wrapString;
                switch (wrapMode) {
                        case NONE: wrapString = "none"; break;
                        case WORD: wrapString = "word"; break;
                        case CHAR: wrapString = "char"; break;
                        default: UNREACHABLE;
                }
                result = wrapString;
        } else if (propName == "-wrapw") {
                result = wrapw;
        } else if (propName == "-wraprelw") {
                result = wraprelw;
        } else {
                OSDImageBasedWidget::getProperty(propName, result);
        }
}
 
void OSDText::invalidateLocal()
{
        font = TTFFont(); // clear font
        OSDImageBasedWidget::invalidateLocal();
}
 
 
string_view OSDText::getType() const
{
        return "text";
}
 
vec2 OSDText::getSize(const OutputSurface& /*output*/) const
{
        if (image) {
                return vec2(image->getSize());
        } else {
                // we don't know the dimensions, must be because of an error
                assert(hasError());
                return {};
        }
}
 
uint8_t OSDText::getFadedAlpha() const
{
        return narrow_cast<uint8_t>(narrow_cast<float>(getRGBA(0) & 0xff) * getRecursiveFadeValue());
}
 
std::unique_ptr<GLImage> OSDText::create(OutputSurface& output)
{
        if (text.empty()) {
                return std::make_unique<GLImage>(ivec2(), 0);
        }
        int scale = getScaleFactor(output);
        if (font.empty()) {
                try {
                        font = TTFFont(systemFileContext().resolve(fontFile),
                                       size * scale);
                } catch (MSXException& e) {
                        throw MSXException("Couldn't open font: ", e.getMessage());
                }
        }
        try {
                vec2 pSize = getParent()->getSize(output);
                int maxWidth = narrow_cast<int>(lrintf(wrapw * narrow<float>(scale) + wraprelw * pSize[0]));
                // Width can't be negative, if it is make it zero instead.
                // This will put each character on a different line.
                maxWidth = std::max(0, maxWidth);
 
                // TODO gradient???
                unsigned textRgba = getRGBA(0);
                string wrappedText;
                if (wrapMode == NONE) {
                        wrappedText = text; // don't wrap
                } else if (wrapMode == WORD) {
                        wrappedText = getWordWrappedText(text, maxWidth);
                } else if (wrapMode == CHAR) {
                        wrappedText = getCharWrappedText(text, maxWidth);
                } else {
                        UNREACHABLE;
                }
                // An alternative is to pass vector<string> to TTFFont::render().
                // That way we can avoid join() (in the wrap functions)
                // followed by // StringOp::split() (in TTFFont::render()).
                SDLSurfacePtr surface(font.render(wrappedText,
                                                  narrow_cast<uint8_t>(textRgba >> 24),
                                                  narrow_cast<uint8_t>(textRgba >> 16),
                                                  narrow_cast<uint8_t>(textRgba >>  8)));
                if (surface) {
                        return std::make_unique<GLImage>(std::move(surface));
                } else {
                        return std::make_unique<GLImage>(ivec2(), 0);
                }
        } catch (MSXException& e) {
                throw MSXException("Couldn't render text: ", e.getMessage());
        }
}
 
 
// Search for a position strictly between min and max which also points to the
// start of a (possibly multi-byte) utf8-character. If no such position exits,
// this function returns 'min'.
static constexpr size_t findCharSplitPoint(string_view line, size_t min, size_t max)
{
        auto pos = (min + max) / 2;
        auto beginIt = line.data();
        auto posIt = beginIt + pos;
 
        auto fwdIt = utf8::sync_forward(posIt);
        auto maxIt = beginIt + max;
        assert(fwdIt <= maxIt);
        if (fwdIt != maxIt) {
                return fwdIt - beginIt;
        }
 
        auto bwdIt = utf8::sync_backward(posIt);
        auto minIt = beginIt + min;
        assert(minIt <= bwdIt); (void)minIt;
        return bwdIt - beginIt;
}
 
// Search for a position that's strictly between min and max and which points
// to a character directly following a delimiter character. if no such position
// exits, this function returns 'min'.
// This function works correctly with multi-byte utf8-encoding as long as
// all delimiter characters are single byte chars.
static constexpr size_t findWordSplitPoint(string_view line, size_t min, size_t max)
{
        constexpr const char* const delimiters = " -/";
 
        // initial guess for a good position
        assert(min < max);
        size_t pos = (min + max) / 2;
        if (pos == min) {
                // can't reduce further
                return min;
        }
 
        // try searching backward (this also checks current position)
        assert(pos > min);
        if (auto pos2 = line.substr(min, pos - min).find_last_of(delimiters);
            pos2 != string_view::npos) {
                pos2 += min + 1;
                assert(min < pos2);
                assert(pos2 <= pos);
                return pos2;
        }
 
        // try searching forward
        if (auto pos2 = line.substr(pos, max - pos).find_first_of(delimiters);
            pos2 != string_view::npos) {
                pos2 += pos;
                assert(pos2 < max);
                pos2 += 1; // char directly after a delimiter;
                if (pos2 < max) {
                        return pos2;
                }
        }
 
        return min;
}
 
static constexpr size_t takeSingleChar(string_view /*line*/, unsigned /*maxWidth*/)
{
        return 1;
}
 
template<typename FindSplitPointFunc, typename CantSplitFunc>
size_t OSDText::split(const string& line, unsigned maxWidth,
                      FindSplitPointFunc findSplitPoint,
                      CantSplitFunc cantSplit,
                      bool removeTrailingSpaces) const
{
        if (line.empty()) {
                // empty line always fits (explicitly handle this because
                // SDL_TTF can't handle empty strings)
                return 0;
        }
 
        unsigned width = font.getSize(line)[0];
        if (width <= maxWidth) {
                // whole line fits
                return line.size();
        }
 
        // binary search till we found the largest initial substring that is
        // not wider than maxWidth
        size_t min = 0;
        size_t max = line.size();
        // invariant: line.substr(0, min) DOES     fit
        //            line.substr(0, max) DOES NOT fit
        size_t cur = findSplitPoint(line, min, max);
        if (cur == 0) {
                // Could not find a valid split point, then split on char
                // (this also handles the case of a single too wide char)
                return cantSplit(line, maxWidth);
        }
        while (true) {
                assert(min < cur);
                assert(cur < max);
                string curStr = line.substr(0, cur);
                if (removeTrailingSpaces) {
                        StringOp::trimRight(curStr, ' ');
                }
                unsigned width2 = font.getSize(curStr)[0];
                if (width2 <= maxWidth) {
                        // still fits, try to enlarge
                        size_t next = findSplitPoint(line, cur, max);
                        if (next == cur) {
                                return cur;
                        }
                        min = cur;
                        cur = next;
                } else {
                        // doesn't fit anymore, try to shrink
                        size_t next = findSplitPoint(line, min, cur);
                        if (next == min) {
                                if (min == 0) {
                                        // even the first word does not fit,
                                        // split on char (see above)
                                        return cantSplit(line, maxWidth);
                                }
                                return min;
                        }
                        max = cur;
                        cur = next;
                }
        }
}
 
size_t OSDText::splitAtChar(const std::string& line, unsigned maxWidth) const
{
        return split(line, maxWidth, findCharSplitPoint, takeSingleChar, false);
}
 
struct SplitAtChar {
        explicit SplitAtChar(const OSDText& osdText_) : osdText(osdText_) {}
        size_t operator()(const string& line, unsigned maxWidth) {
                return osdText.splitAtChar(line, maxWidth);
        }
        const OSDText& osdText;
};
size_t OSDText::splitAtWord(const std::string& line, unsigned maxWidth) const
{
        return split(line, maxWidth, findWordSplitPoint, SplitAtChar(*this), true);
}
 
string OSDText::getCharWrappedText(const string& txt, unsigned maxWidth) const
{
        std::vector<string_view> wrappedLines;
        for (auto line : StringOp::split_view(txt, '\n')) {
                do {
                        auto p = splitAtChar(string(line), maxWidth);
                        wrappedLines.push_back(line.substr(0, p));
                        line = line.substr(p);
                } while (!line.empty());
        }
        return join(wrappedLines, '\n');
}
 
string OSDText::getWordWrappedText(const string& txt, unsigned maxWidth) const
{
        std::vector<string_view> wrappedLines;
        for (auto line : StringOp::split_view(txt, '\n')) {
                do {
                        auto p = splitAtWord(string(line), maxWidth);
                        string_view first = line.substr(0, p);
                        StringOp::trimRight(first, ' '); // remove trailing spaces
                        wrappedLines.push_back(first);
                        line = line.substr(p);
                        StringOp::trimLeft(line, ' '); // remove leading spaces
                } while (!line.empty());
        }
        return join(wrappedLines, '\n');
}
 
} // namespace openmsx