svg_loader: handle text node

The text node is handled, but default values
of the font-family and font-size as used in
the user's system are not.
For now font has to be loaded by the user.

@Issue: https://github.com/thorvg/thorvg/issues/2350

src/loaders/svg/tvgSvgLoader.cpp

@@ -2119,7 +2119,72 @@ static SvgNode* _createUseNode(SvgLoaderData* loader, SvgNode* parent, const cha
 }
 
 
-//TODO: Implement 'text' primitive
+static constexpr struct
+{
+    const char* tag;
+    SvgParserLengthType type;
+    int sz;
+    size_t offset;
+} textTags[] = {
+        {"x", SvgParserLengthType::Horizontal, sizeof("x"), offsetof(SvgTextNode, x)},
+        {"y", SvgParserLengthType::Vertical, sizeof("y"), offsetof(SvgTextNode, y)},
+        {"font-size", SvgParserLengthType::Vertical, sizeof("font-size"), offsetof(SvgTextNode, fontSize)}
+};
+
+
+static bool _attrParseTextNode(void* data, const char* key, const char* value)
+{
+    SvgLoaderData* loader = (SvgLoaderData*)data;
+    SvgNode* node = loader->svgParse->node;
+    SvgTextNode* text = &(node->node.text);
+
+    unsigned char* array;
+    int sz = strlen(key);
+
+    array = (unsigned char*)text;
+    for (unsigned int i = 0; i < sizeof(textTags) / sizeof(textTags[0]); i++) {
+        if (textTags[i].sz - 1 == sz && !strncmp(textTags[i].tag, key, sz)) {
+            *((float*)(array + textTags[i].offset)) = _toFloat(loader->svgParse, value, textTags[i].type);
+            return true;
+        }
+    }
+
+    if (!strcmp(key, "font-family")) {
+        if (text->fontFamily && value) free(text->fontFamily);
+        text->fontFamily = strdup(value);
+    } else if (!strcmp(key, "style")) {
+        return simpleXmlParseW3CAttribute(value, strlen(value), _parseStyleAttr, loader);
+    } else if (!strcmp(key, "clip-path")) {
+        _handleClipPathAttr(loader, node, value);
+    } else if (!strcmp(key, "mask")) {
+        _handleMaskAttr(loader, node, value);
+    } else if (!strcmp(key, "id")) {
+        if (node->id && value) free(node->id);
+        node->id = _copyId(value);
+    } else if (!strcmp(key, "class")) {
+        _handleCssClassAttr(loader, node, value);
+    } else {
+        return _parseStyleAttr(loader, key, value, false);
+    }
+    return true;
+}
+
+
+static SvgNode* _createTextNode(SvgLoaderData* loader, SvgNode* parent, const char* buf, unsigned bufLength, parseAttributes func)
+{
+    loader->svgParse->node = _createNode(parent, SvgNodeType::Text);
+    if (!loader->svgParse->node) return nullptr;
+
+    //TODO: support the def font and size as used in a system?
+    loader->svgParse->node->node.text.fontSize = 10.0f;
+    loader->svgParse->node->node.text.fontFamily = nullptr;
+
+    func(buf, bufLength, _attrParseTextNode, loader);
+
+    return loader->svgParse->node;
+}
+
+
 static constexpr struct
 {
     const char* tag;
@@ -2134,7 +2199,8 @@ static constexpr struct
     {"rect", sizeof("rect"), _createRectNode},
     {"polyline", sizeof("polyline"), _createPolylineNode},
     {"line", sizeof("line"), _createLineNode},
-    {"image", sizeof("image"), _createImageNode}
+    {"image", sizeof("image"), _createImageNode},
+    {"text", sizeof("text"), _createTextNode}
 };
 
 
@@ -3122,6 +3188,20 @@ static void _copyAttr(SvgNode* to, const SvgNode* from)
             to->node.use.symbol = from->node.use.symbol;
             break;
         }
+        case SvgNodeType::Text: {
+            to->node.text.x = from->node.text.x;
+            to->node.text.y = from->node.text.y;
+            to->node.text.fontSize = from->node.text.fontSize;
+            if (from->node.text.text) {
+                if (to->node.text.text) free(to->node.text.text);
+                to->node.text.text = strdup(from->node.text.text);
+            }
+            if (from->node.text.fontFamily) {
+                if (to->node.text.fontFamily) free(to->node.text.fontFamily);
+                to->node.text.fontFamily = strdup(from->node.text.fontFamily);
+            }
+            break;
+        }
         default: {
             break;
         }
@@ -3244,7 +3324,7 @@ static void _svgLoaderParserXmlOpen(SvgLoaderData* loader, const char* content,
                     node = method(loader, nullptr, attrs, attrsLength, simpleXmlParseAttributes);
                     loader->cssStyle = node;
                     loader->doc->node.doc.style = node;
-                    loader->style = true;
+                    loader->openedTag = OpenedTagType::Style;
                 }
             } else {
                 node = method(loader, parent, attrs, attrsLength, simpleXmlParseAttributes);
@@ -3260,9 +3340,12 @@ static void _svgLoaderParserXmlOpen(SvgLoaderData* loader, const char* content,
         else parent = loader->doc;
         node = method(loader, parent, attrs, attrsLength, simpleXmlParseAttributes);
         if (node && !empty) {
-            auto defs = _createDefsNode(loader, nullptr, nullptr, 0, nullptr);
+            if (!strcmp(tagName, "text")) loader->openedTag = OpenedTagType::Text;
-            loader->stack.push(defs);
+            else {
-            loader->currentGraphicsNode = node;
+                auto defs = _createDefsNode(loader, nullptr, nullptr, 0, nullptr);
+                loader->stack.push(defs);
+                loader->currentGraphicsNode = node;
+            }
         }
     } else if ((gradientMethod = _findGradientFactory(tagName))) {
         SvgStyleGradient* gradient;
@@ -3295,6 +3378,15 @@ static void _svgLoaderParserXmlOpen(SvgLoaderData* loader, const char* content,
 }
 
 
+static void _svgLoaderParserText(SvgLoaderData* loader, const char* content, unsigned int length)
+{
+    auto text = &loader->svgParse->node->node.text;
+    if (text->text) free(text->text);
+    text->text = strDuplicate(content, length);
+    loader->openedTag = OpenedTagType::Other;
+}
+
+
 static void _svgLoaderParserXmlCssStyle(SvgLoaderData* loader, const char* content, unsigned int length)
 {
     char* tag;
@@ -3327,7 +3419,7 @@ static void _svgLoaderParserXmlCssStyle(SvgLoaderData* loader, const char* conte
         free(tag);
         free(name);
     }
-    loader->style = false;
+    loader->openedTag = OpenedTagType::Other;
 }
 
 
@@ -3350,7 +3442,8 @@ static bool _svgLoaderParser(void* data, SimpleXMLType type, const char* content
         }
         case SimpleXMLType::Data:
         case SimpleXMLType::CData: {
-            if (loader->style) _svgLoaderParserXmlCssStyle(loader, content, length);
+            if (loader->openedTag == OpenedTagType::Style) _svgLoaderParserXmlCssStyle(loader, content, length);
+            else if (loader->openedTag == OpenedTagType::Text) _svgLoaderParserText(loader, content, length);
             break;
         }
         case SimpleXMLType::DoctypeChild: {
@@ -3572,6 +3665,11 @@ static void _freeNode(SvgNode* node)
              free(node->node.image.href);
              break;
          }
+         case SvgNodeType::Text: {
+             free(node->node.text.text);
+             free(node->node.text.fontFamily);
+             break;
+         }
          default: {
              break;
          }

src/loaders/svg/tvgSvgLoaderCommon.h

@@ -374,6 +374,14 @@ struct SvgCssStyleNode
 {
 };
 
+struct SvgTextNode
+{
+    char* text;
+    char* fontFamily;
+    float x, y;
+    float fontSize;
+};
+
 struct SvgLinearGradient
 {
     float x1;
@@ -518,6 +526,7 @@ struct SvgNode
         SvgClipNode clip;
         SvgCssStyleNode cssStyle;
         SvgSymbolNode symbol;
+        SvgTextNode text;
     } node;
     ~SvgNode();
 };
@@ -545,6 +554,13 @@ struct SvgNodeIdPair
     char *id;
 };
 
+enum class OpenedTagType : uint8_t
+{
+    Other = 0,
+    Style,
+    Text
+};
+
 struct SvgLoaderData
 {
     Array<SvgNode*> stack;
@@ -559,7 +575,7 @@ struct SvgLoaderData
     Array<char*> images;        //embedded images
     int level = 0;
     bool result = false;
-    bool style = false;
+    OpenedTagType openedTag = OpenedTagType::Other;
     SvgNode* currentGraphicsNode = nullptr;
 };
 

src/loaders/svg/tvgSvgSceneBuilder.cpp

@@ -67,6 +67,14 @@ static Box _boundingBox(const Shape* shape)
 }
 
 
+static Box _boundingBox(const Text* text)
+{
+    float x, y, w, h;
+    text->bounds(&x, &y, &w, &h, false);
+    return {x, y, w, h};
+}
+
+
 static void _transformMultiply(const Matrix* mBBox, Matrix* gradTransf)
 {
     gradTransf->e13 = gradTransf->e13 * mBBox->e11 + mBBox->e13;
@@ -320,14 +328,15 @@ static void _applyProperty(SvgLoaderData& loaderData, SvgNode* node, Shape* vg,
         if (!style->fill.paint.gradient->userSpace) bBox = _boundingBox(vg);
 
         if (style->fill.paint.gradient->type == SvgGradientType::Linear) {
-             auto linear = _applyLinearGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
+            auto linear = _applyLinearGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
-             vg->fill(std::move(linear));
+            vg->fill(std::move(linear));
         } else if (style->fill.paint.gradient->type == SvgGradientType::Radial) {
-             auto radial = _applyRadialGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
+            auto radial = _applyRadialGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
-             vg->fill(std::move(radial));
+            vg->fill(std::move(radial));
         }
     } else if (style->fill.paint.url) {
         //TODO: Apply the color pointed by url
+        TVGLOG("SVG", "The fill's url not supported.");
     } else if (style->fill.paint.curColor) {
         //Apply the current style color
         vg->fill(style->color.r, style->color.g, style->color.b, style->fill.opacity);
@@ -371,6 +380,7 @@ static void _applyProperty(SvgLoaderData& loaderData, SvgNode* node, Shape* vg,
         }
     } else if (style->stroke.paint.url) {
         //TODO: Apply the color pointed by url
+        TVGLOG("SVG", "The stroke's url not supported.");
     } else if (style->stroke.paint.curColor) {
         //Apply the current style color
         vg->strokeFill(style->color.r, style->color.g, style->color.b, style->stroke.opacity);
@@ -772,6 +782,61 @@ static unique_ptr<Scene> _useBuildHelper(SvgLoaderData& loaderData, const SvgNod
 }
 
 
+static void _applyTextFill(SvgStyleProperty* style, Text* text, const Box& vBox)
+{
+    //If fill property is nullptr then do nothing
+    if (style->fill.paint.none) {
+        //Do nothing
+    } else if (style->fill.paint.gradient) {
+        Box bBox = vBox;
+        if (!style->fill.paint.gradient->userSpace) bBox = _boundingBox(text);
+
+        if (style->fill.paint.gradient->type == SvgGradientType::Linear) {
+            auto linear = _applyLinearGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
+            text->fill(std::move(linear));
+        } else if (style->fill.paint.gradient->type == SvgGradientType::Radial) {
+            auto radial = _applyRadialGradientProperty(style->fill.paint.gradient, bBox, style->fill.opacity);
+            text->fill(std::move(radial));
+        }
+    } else if (style->fill.paint.url) {
+        //TODO: Apply the color pointed by url
+        TVGLOG("SVG", "The fill's url not supported.");
+    } else if (style->fill.paint.curColor) {
+        //Apply the current style color
+        text->fill(style->color.r, style->color.g, style->color.b);
+        text->opacity(style->fill.opacity);
+    } else {
+        //Apply the fill color
+        text->fill(style->fill.paint.color.r, style->fill.paint.color.g, style->fill.paint.color.b);
+        text->opacity(style->fill.opacity);
+    }
+}
+
+
+static unique_ptr<Text> _textBuildHelper(SvgLoaderData& loaderData, const SvgNode* node, const Box& vBox, const string& svgPath)
+{
+    auto textNode = &node->node.text;
+    if (!textNode->text) return nullptr;
+    auto text = Text::gen();
+
+    Matrix textTransform = {1, 0, 0, 0, 1, 0, 0, 0, 1};
+    if (node->transform) textTransform = *node->transform;
+    mathTranslateR(&textTransform, node->node.text.x, node->node.text.y - textNode->fontSize);
+    text->transform(textTransform);
+
+    //TODO: handle def values of font and size as used in a system?
+    const float ptPerPx = 0.75f; //1 pt = 1/72; 1 in = 96 px; -> 72/96 = 0.75
+    auto fontSizePt = textNode->fontSize * ptPerPx;
+    if (textNode->fontFamily) text->font(textNode->fontFamily, fontSizePt);
+    text->text(textNode->text);
+
+    _applyTextFill(node->style, text.get(), vBox);
+    _applyComposition(loaderData, text.get(), node, vBox, svgPath);
+
+    return text;
+}
+
+
 static unique_ptr<Scene> _sceneBuildHelper(SvgLoaderData& loaderData, const SvgNode* node, const Box& vBox, const string& svgPath, bool mask, int depth, bool* isMaskWhite)
 {
     /* Exception handling: Prevent invalid SVG data input.
@@ -800,6 +865,9 @@ static unique_ptr<Scene> _sceneBuildHelper(SvgLoaderData& loaderData, const SvgN
                         scene->push(std::move(image));
                         if (isMaskWhite) *isMaskWhite = false;
                     }
+                } else if ((*child)->type == SvgNodeType::Text) {
+                    auto text = _textBuildHelper(loaderData, *child, vBox, svgPath);
+                    if (text) scene->push(std::move(text));
                 } else if ((*child)->type != SvgNodeType::Mask) {
                     auto shape = _shapeBuildHelper(loaderData, *child, vBox, svgPath);
                     if (shape) {