text-wrapping + fix

src/graphics/ui/elements/Label.cpp

@@ -7,30 +7,50 @@
 
 using namespace gui;
 
-void LabelCache::update(const std::wstring& text, bool multiline) {
+void LabelCache::prepare(Font* font, size_t wrapWidth) {
+    if (font != this->font) {
+        resetFlag = true;
+        this->font = font;
+    }
+    if (wrapWidth != this->wrapWidth) {
+        resetFlag = true;
+        this->wrapWidth = wrapWidth;
+    }
+}
+
+void LabelCache::update(const std::wstring& text, bool multiline, bool wrap) {
     resetFlag = false;
     lines.clear();
+    lines.push_back(LineScheme {0, false});
 
+    if (font == nullptr) {
+        wrap = false;
+    }
+    size_t len = 0;
     if (multiline) {
-        lines.push_back(LineScheme {0});
-        for (size_t i = 0; i < text.length(); i++) {
+        for (size_t i = 0; i < text.length(); i++, len++) {
             if (text[i] == L'\n') {
-                lines.push_back(LineScheme {i+1});
+                lines.push_back(LineScheme {i+1, false});
+                len = 0;
+            } else if (i > 0 && wrap && text[i+1] != L'\n') {
+                size_t width = font->calcWidth(text, i-len-1, i-(i-len)+2);
+                if (width >= wrapWidth) {
+                    // starting a fake line
+                    lines.push_back(LineScheme {i+1, true});
+                    len = 0;
+                }
             }
         }
     }
-    if (lines.empty()) {
-        lines.push_back(LineScheme {0});
-    }
 }
 
 Label::Label(std::string text, std::string fontName) 
-  : UINode(glm::vec2(text.length() * 8, 15)), 
+  : UINode(glm::vec2(text.length() * 8, 15)),
     text(util::str2wstr_utf8(text)), 
     fontName(fontName) 
 {
     setInteractive(false);
-    cache.update(this->text, multiline);
+    cache.update(this->text, multiline, textWrap);
 }
 
 
@@ -40,7 +60,7 @@ Label::Label(std::wstring text, std::string fontName)
     fontName(fontName) 
 {
     setInteractive(false);
-    cache.update(this->text, multiline);
+    cache.update(this->text, multiline, textWrap);
 }
 
 void Label::setText(std::wstring text) {
@@ -48,7 +68,7 @@ void Label::setText(std::wstring text) {
         return;
     }
     this->text = text;
-    cache.update(this->text, multiline);
+    cache.update(this->text, multiline, textWrap);
 }
 
 const std::wstring& Label::getText() const {
@@ -88,6 +108,11 @@ size_t Label::getTextLineOffset(size_t line) const {
     return cache.lines.at(line).offset;
 }
 
+bool Label::isFakeLine(size_t line) const {
+    line = std::min(cache.lines.size()-1, line);
+    return cache.lines.at(line).fake;
+}
+
 int Label::getLineYOffset(uint line) const {
     return line * totalLineHeight + textYOffset;
 }
@@ -113,12 +138,16 @@ uint Label::getLinesNumber() const {
 }
 
 void Label::draw(const GfxContext* pctx, Assets* assets) {
+    auto batch = pctx->getBatch2D();
+    auto font = assets->getFont(fontName);
+    cache.prepare(font, static_cast<size_t>(glm::abs(getSize().x)));
+
     if (supplier) {
         setText(supplier());
     }
-
-    auto batch = pctx->getBatch2D();
-    auto font = assets->getFont(fontName);
+    if (cache.resetFlag) {
+        cache.update(text, multiline, textWrap);
+    }
 
     batch->setColor(getColor());
 
@@ -157,13 +186,12 @@ void Label::draw(const GfxContext* pctx, Assets* assets) {
     totalLineHeight = lineHeight;
 
     if (multiline) {
-        size_t offset = 0;
-        for (uint i = 0; i < cache.lines.size(); i++) {
+        for (size_t i = 0; i < cache.lines.size(); i++) {
+            auto& line = cache.lines.at(i);
+            size_t offset = line.offset;
             std::wstring_view view(text.c_str()+offset, text.length()-offset);
-            size_t end = view.find(L'\n');
-            if (end != std::wstring::npos) {
-                view = std::wstring_view(text.c_str()+offset, end);
-                offset += end + 1;
+            if (i < cache.lines.size()-1) {
+                view = std::wstring_view(text.c_str()+offset, cache.lines.at(i+1).offset-offset);
             }
             font->draw(batch, view, pos.x, pos.y + i * totalLineHeight, FontStyle::none);
         }
@@ -187,3 +215,12 @@ void Label::setMultiline(bool multiline) {
 bool Label::isMultiline() const {
     return multiline;
 }
+
+void Label::setTextWrapping(bool flag) {
+    this->textWrap = flag;
+    cache.resetFlag = true;
+}
+
+bool Label::isTextWrapping() const {
+    return textWrap;
+}