Add Document::updateLayout function

include/lunasvg.h

@@ -644,7 +644,7 @@ class LUNASVG_API Element : public Node {
 
 private:
     Element(SVGElement* element);
-    SVGElement* element() const;
+    SVGElement* element(bool layout = false) const;
     friend class Node;
     friend class Document;
 };
@@ -707,10 +707,15 @@ class LUNASVG_API Document {
     Box boundingBox() const;
 
     /**
-     * @brief Updates the layout of the document.
+     * @brief Updates the layout of the document if needed.
      */
     void updateLayout();
 
+    /**
+     * @brief Forces an immediate layout update.
+     */
+    void forceLayout();
+
     /**
      * @brief Renders the document onto a bitmap using a transformation matrix.
      * @param bitmap The bitmap to render onto.

source/lunasvg.cpp

@@ -1,6 +1,5 @@
 #include "lunasvg.h"
 #include "svgelement.h"
-#include "svglayoutstate.h"
 #include "svgrenderstate.h"
 
 #include <cstring>
@@ -336,14 +335,14 @@ void Element::render(Bitmap& bitmap, const Matrix& matrix) const
         return;
     auto canvas = Canvas::create(bitmap);
     SVGRenderState state(nullptr, nullptr, matrix, SVGRenderMode::Painting, canvas);
-    element()->render(state);
+    element(true)->render(state);
 }
 
 Bitmap Element::renderToBitmap(int width, int height, uint32_t backgroundColor) const
 {
     if(m_node == nullptr)
         return Bitmap();
-    auto elementBounds = element()->localTransform().mapRect(element()->paintBoundingBox());
+    auto elementBounds = element(true)->localTransform().mapRect(element()->paintBoundingBox());
     if(elementBounds.isEmpty())
         return Bitmap();
     if(width <= 0 && height <= 0) {
@@ -368,15 +367,15 @@ Bitmap Element::renderToBitmap(int width, int height, uint32_t backgroundColor)
 Matrix Element::getLocalMatrix() const
 {
     if(m_node)
-        return element()->localTransform();
+        return element(true)->localTransform();
     return Matrix();
 }
 
 Matrix Element::getGlobalMatrix() const
 {
     if(m_node == nullptr)
         return Matrix();
-    auto transform = element()->localTransform();
+    auto transform = element(true)->localTransform();
     for(auto parent = element()->parent(); parent; parent = parent->parent())
         transform.postMultiply(parent->localTransform());
     return transform;
@@ -395,7 +394,7 @@ Box Element::getGlobalBoundingBox() const
 Box Element::getBoundingBox() const
 {
     if(m_node)
-        return element()->paintBoundingBox();
+        return element(true)->paintBoundingBox();
     return Box();
 }
 
@@ -409,9 +408,12 @@ NodeList Element::children() const
     return children;
 }
 
-SVGElement* Element::element() const
+SVGElement* Element::element(bool layout) const
 {
-    return static_cast<SVGElement*>(m_node);
+    auto element = static_cast<SVGElement*>(m_node);
+    if(element && layout)
+        element->rootElement()->updateLayout();
+    return element;
 }
 
 std::unique_ptr<Document> Document::loadFromFile(const std::string& filename)
@@ -441,29 +443,32 @@ std::unique_ptr<Document> Document::loadFromData(const char* data, size_t length
     std::unique_ptr<Document> document(new Document);
     if(!document->parse(data, length))
         return nullptr;
-    document->updateLayout();
     return document;
 }
 
 float Document::width() const
 {
-    return m_rootElement->intrinsicWidth();
+    return m_rootElement->updateLayout()->intrinsicWidth();
 }
 
 float Document::height() const
 {
-    return m_rootElement->intrinsicHeight();
+    return m_rootElement->updateLayout()->intrinsicHeight();
 }
 
 Box Document::boundingBox() const
 {
-    return m_rootElement->localTransform().mapRect(m_rootElement->paintBoundingBox());
+    return m_rootElement->updateLayout()->localTransform().mapRect(m_rootElement->paintBoundingBox());
 }
 
 void Document::updateLayout()
 {
-    SVGLayoutState state;
-    m_rootElement->layout(state);
+    m_rootElement->updateLayout();
+}
+
+void Document::forceLayout()
+{
+    m_rootElement->forceLayout();
 }
 
 void Document::render(Bitmap& bitmap, const Matrix& matrix) const
@@ -472,24 +477,26 @@ void Document::render(Bitmap& bitmap, const Matrix& matrix) const
         return;
     auto canvas = Canvas::create(bitmap);
     SVGRenderState state(nullptr, nullptr, matrix, SVGRenderMode::Painting, canvas);
-    m_rootElement->render(state);
+    m_rootElement->updateLayout()->render(state);
 }
 
 Bitmap Document::renderToBitmap(int width, int height, uint32_t backgroundColor) const
 {
-    if(!m_rootElement->intrinsicWidth() || !m_rootElement->intrinsicHeight())
+    auto intrinsicWidth = m_rootElement->updateLayout()->intrinsicWidth();
+    auto intrinsicHeight = m_rootElement->intrinsicHeight();
+    if(intrinsicWidth == 0.f || intrinsicHeight == 0.f)
         return Bitmap();
     if(width <= 0 && height <= 0) {
-        width = static_cast<int>(std::ceil(m_rootElement->intrinsicWidth()));
-        height = static_cast<int>(std::ceil(m_rootElement->intrinsicHeight()));
+        width = static_cast<int>(std::ceil(intrinsicWidth));
+        height = static_cast<int>(std::ceil(intrinsicHeight));
     } else if(width > 0 && height <= 0) {
-        height = static_cast<int>(std::ceil(width * m_rootElement->intrinsicHeight() / m_rootElement->intrinsicWidth()));
+        height = static_cast<int>(std::ceil(width * intrinsicHeight / intrinsicWidth));
     } else if(height > 0 && width <= 0) {
-        width = static_cast<int>(std::ceil(height * m_rootElement->intrinsicWidth() / m_rootElement->intrinsicHeight()));
+        width = static_cast<int>(std::ceil(height * intrinsicWidth / intrinsicHeight));
     }
 
-    auto xScale = width / m_rootElement->intrinsicWidth();
-    auto yScale = height / m_rootElement->intrinsicHeight();
+    auto xScale = width / intrinsicWidth;
+    auto yScale = height / intrinsicHeight;
 
     Matrix matrix(xScale, 0, 0, yScale, 0, 0);
     Bitmap bitmap(width, height);

source/svgelement.cpp

@@ -214,6 +214,7 @@ bool SVGElement::setAttribute(const Attribute& attribute)
 
 void SVGElement::parseAttribute(PropertyID id, const std::string& value)
 {
+    rootElement()->setNeedsLayout();
     if(auto property = getProperty(id)) {
         property->parse(value);
     }
@@ -618,6 +619,13 @@ SVGRootElement::SVGRootElement(Document* document)
 {
 }
 
+SVGRootElement* SVGRootElement::updateLayout()
+{
+    if(needsLayout())
+        forceLayout();
+    return this;
+}
+
 SVGElement* SVGRootElement::getElementById(const std::string_view& id) const
 {
     auto it = m_idCache.find(id);
@@ -673,6 +681,12 @@ void SVGRootElement::layout(SVGLayoutState& state)
     }
 }
 
+void SVGRootElement::forceLayout()
+{
+    SVGLayoutState state;
+    layout(state);
+}
+
 SVGUseElement::SVGUseElement(Document* document)
     : SVGGraphicsElement(document, ElementID::Use)
     , SVGURIReference(this)

source/svgelement.h

@@ -334,14 +334,21 @@ class SVGRootElement final : public SVGSVGElement {
     float intrinsicWidth() const { return m_intrinsicWidth; }
     float intrinsicHeight() const { return m_intrinsicHeight; }
 
+    void setNeedsLayout() { m_intrinsicWidth = -1.f; }
+    bool needsLayout() const { return m_intrinsicWidth == -1.f; }
+
+    SVGRootElement* updateLayout();
+
     SVGElement* getElementById(const std::string_view& id) const;
     void addElementById(const std::string& id, SVGElement* element);
     void layout(SVGLayoutState& state) final;
 
+    void forceLayout();
+
 private:
     std::map<std::string, SVGElement*, std::less<>> m_idCache;
-    float m_intrinsicWidth{0};
-    float m_intrinsicHeight{0};
+    float m_intrinsicWidth{-1.f};
+    float m_intrinsicHeight{-1.f};
 };
 
 class SVGUseElement final : public SVGGraphicsElement, public SVGURIReference {