svg_loader: proper svg resizing

Solves the problem of 'vx' and 'vy' < 0 and cases with 'width'
and 'height' values different than widht and height from the 'viewBox'
attribute.

src/loaders/svg/tvgSvgLoader.cpp

@@ -2770,7 +2770,7 @@ void SvgLoader::run(unsigned tid)
 
         if (loaderData.cloneNodes.count > 0) _clonePostponedNodes(&loaderData.cloneNodes);
     }
-    root = svgSceneBuild(loaderData.doc, vx, vy, vw, vh);
+    root = svgSceneBuild(loaderData.doc, vx, vy, vw, vh, w, h, preserveAspect);
 };
 
 
@@ -2855,31 +2855,31 @@ bool SvgLoader::resize(Paint* paint, float w, float h)
 {
     if (!paint) return false;
 
-    auto sx = w / vw;
+    auto sx = w / this->w;
-    auto sy = h / vh;
+    auto sy = h / this->h;
 
     if (preserveAspect) {
         //Scale
         auto scale = sx < sy ? sx : sy;
         paint->scale(scale);
         //Align
-        auto vx = this->vx * scale;
+        auto tx = 0.0f;
-        auto vy = this->vy * scale;
+        auto ty = 0.0f;
-        auto vw = this->vw * scale;
+        auto tw = this->w * scale;
-        auto vh = this->vh * scale;
+        auto th = this->h * scale;
-        if (vw > vh) vy -= (h - vh) * 0.5f;
+        if (tw > th) ty -= (h - th) * 0.5f;
-        else vx -= (w - vw) * 0.5f;
+        else tx -= (w - tw) * 0.5f;
-        paint->translate(-vx, -vy);
+        paint->translate(-tx, -ty);
     } else {
         //Align
-        auto vx = this->vx * sx;
+        auto tx = 0.0f;
-        auto vy = this->vy * sy;
+        auto ty = 0.0f;
-        auto vw = this->vw * sx;
+        auto tw = this->w * sx;
-        auto vh = this->vh * sy;
+        auto th = this->h * sy;
-        if (vw > vh) vy -= (h - vh) * 0.5f;
+        if (tw > th) ty -= (h - th) * 0.5f;
-        else vx -= (w - vw) * 0.5f;
+        else tx -= (w - tw) * 0.5f;
 
-        Matrix m = {sx, 0, -vx, 0, sy, -vy, 0, 0, 1};
+        Matrix m = {sx, 0, -tx, 0, sy, -ty, 0, 0, 1};
         paint->transform(m);
     }
     return true;

src/loaders/svg/tvgSvgSceneBuilder.cpp

@@ -25,6 +25,7 @@
 #include "tvgSvgSceneBuilder.h"
 #include "tvgSvgPath.h"
 #include "tvgSvgUtil.h"
+#include <float.h>
 
 static bool _appendShape(SvgNode* node, Shape* shape, float vx, float vy, float vw, float vh);
 
@@ -516,14 +517,45 @@ static unique_ptr<Scene> _sceneBuildHelper(const SvgNode* node, float vx, float
 /* External Class Implementation                                        */
 /************************************************************************/
 
-unique_ptr<Scene> svgSceneBuild(SvgNode* node, float vx, float vy, float vw, float vh)
+unique_ptr<Scene> svgSceneBuild(SvgNode* node, float vx, float vy, float vw, float vh, float w, float h, bool preserveAspect)
 {
     if (!node || (node->type != SvgNodeType::Doc)) return nullptr;
 
     auto docNode = _sceneBuildHelper(node, vx, vy, vw, vh);
 
+    if (fabsf(w - vw) > FLT_EPSILON || fabsf(h - vh) > FLT_EPSILON) {
+        auto sx = w / vw;
+        auto sy = h / vh;
+
+        if (preserveAspect) {
+            //Scale
+            auto scale = sx < sy ? sx : sy;
+            docNode->scale(scale);
+            //Align
+            auto tvx = vx * scale;
+            auto tvy = vy * scale;
+            auto tvw = vw * scale;
+            auto tvh = vh * scale;
+            if (vw > vh) tvy -= (h - tvh) * 0.5f;
+            else  tvx -= (w - tvw) * 0.5f;
+            docNode->translate(-tvx, -tvy);
+        } else {
+            //Align
+            auto tvx = vx * sx;
+            auto tvy = vy * sy;
+            auto tvw = vw * sx;
+            auto tvh = vh * sy;
+            if (tvw > tvh) tvy -= (h - tvh) * 0.5f;
+            else tvx -= (w - tvw) * 0.5f;
+            Matrix m = {sx, 0, -tvx, 0, sy, -tvy, 0, 0, 1};
+            docNode->transform(m);
+        }
+    } else if (vx < 0 || vy < 0) {
+        docNode->translate(-vx, -vy);
+    }
+
     auto viewBoxClip = Shape::gen();
-    viewBoxClip->appendRect(vx, vy, vw, vh, 0, 0);
+    viewBoxClip->appendRect(0, 0, w, h, 0, 0);
     viewBoxClip->fill(0, 0, 0, 255);
 
     auto compositeLayer = Scene::gen();

src/loaders/svg/tvgSvgSceneBuilder.h

@@ -25,6 +25,6 @@
 
 #include "tvgCommon.h"
 
-unique_ptr<Scene> svgSceneBuild(SvgNode* node, float vx, float vy, float vw, float vh);
+unique_ptr<Scene> svgSceneBuild(SvgNode* node, float vx, float vy, float vw, float vh, float w, float h, bool preserveAspect);
 
 #endif //_TVG_SVG_SCENE_BUILDER_H_