CairoHelper: fix scale

Author: rodlie

Helpers/CairoHelper.cpp

@@ -45,6 +45,17 @@ CairoHelper::applyScale(cairo_t *cr,
     cairo_scale(cr, scale.x, scale.y);
 }
 
+void
+CairoHelper::applyScale(cairo_t *cr,
+                        const _XY &scale,
+                        const _XY &origin)
+{
+    if (!cr || (scale.x == 0. && scale.y == 0.)) { return; }
+    cairo_translate(cr, origin.x, origin.y);
+    cairo_scale(cr, scale.x, scale.y);
+    cairo_translate(cr, -origin.x, -origin.y);
+}
+
 void
 CairoHelper::applySkew(cairo_t *cr,
                        const _XY &skew,
@@ -83,7 +94,7 @@ CairoHelper::applyTransform(cairo_t *cr,
     if (!cr) { return; }
     if (transform.flip) { applyFlip(cr, transform.height); }
     if (transform.position) { applyPosition(cr, transform.origin); }
-    applyScale(cr, transform.scale);
+    applyScale(cr, transform.scale, transform.origin);
     applySkew(cr, transform.skew, transform.origin);
     applyRotate(cr, transform.rotate, transform.origin);
 }

Helpers/CairoHelper.h

@@ -49,6 +49,9 @@ class CairoHelper
     /** @brief apply scale */
     static void applyScale(cairo_t *cr,
                            const _XY &scale);
+    static void applyScale(cairo_t *cr,
+                           const _XY &scale,
+                           const _XY &origin);
     /** @brief apply skew */
     static void applySkew(cairo_t *cr,
                           const _XY &skew,