[PATCH] pass correct time events to mypaint brush engine

[Martin Renold]

Use the event time, instead of the time when the line is rendered.
Reset the brush engine properly between strokes, since we don't have
access to motion events without pressure.
---
 krita/plugins/paintops/mypaint/mypaint_paintop.cpp |   49 +++++++++-----------
 krita/plugins/paintops/mypaint/mypaint_paintop.h   |    3 +-
 2 files changed, 23 insertions(+), 29 deletions(-)

diff --git a/krita/plugins/paintops/mypaint/mypaint_paintop.cpp b/krita/plugins/paintops/mypaint/mypaint_paintop.cpp
index c1705e9..c155753 100644
--- a/krita/plugins/paintops/mypaint/mypaint_paintop.cpp
+++ b/krita/plugins/paintops/mypaint/mypaint_paintop.cpp
@@ -41,13 +41,11 @@ MyPaint::MyPaint(const MyPaintSettings *settings, KisPainter * painter, KisImage
     MyPaintFactory *factory = static_cast<MyPaintFactory*>(KisPaintOpRegistry::instance()->get("mypaintbrush"));
     m_brush = factory->brush(settings->getString("filename"));
     m_brush->set_base_value(BRUSH_RADIUS_LOGARITHMIC, settings->getFloat("radius_logarithmic"));
-    m_brush->new_stroke();
     QColor c = painter->paintColor().toQColor();
     qreal h, s, v, a;
     c.getHsvF(&h, &s, &v, &a);
     m_brush->set_color_hsv((float)h, (float)s, (float)v);
-    m_mypaintThinksStrokeHasEnded = false;
-    m_eventTime.start(); // GTK puts timestamps in its events, Qt doesn't, so fake it.
+    m_mustEndPreviousStroke = true;
 }
 
 MyPaint::~MyPaint()
@@ -57,16 +55,8 @@ MyPaint::~MyPaint()
 
 qreal MyPaint::paintAt(const KisPaintInformation& info)
 {
-    if (m_mypaintThinksStrokeHasEnded) {
-        m_settings->brush()->new_stroke();
-    }
-    m_mypaintThinksStrokeHasEnded =
-                        m_brush->stroke_to(m_surface,
-                                           info.pos().x(),
-                                           info.pos().y(),
-                                           info.pressure(),
-                                           qreal(m_eventTime.elapsed()) / 1000);
-    m_eventTime.restart();
+    // never called?
+    Q_UNUSED(info);
     return 1.0;
 }
 
@@ -76,22 +66,27 @@ KisDistanceInformation MyPaint::paintLine(const KisPaintInformation &pi1, const
 
     if (!painter()) return KisDistanceInformation();
 
-    if (m_mypaintThinksStrokeHasEnded) {
-        m_brush->new_stroke();
-    }
-    m_mypaintThinksStrokeHasEnded = m_brush->stroke_to(m_surface,
-                                                       pi1.pos().x(), pi1.pos().y(),
-                                                       0,
-                                                       0);
-    if (m_mypaintThinksStrokeHasEnded) {
-        m_brush->new_stroke();
+    // The MyPaint brush engine is expecting motion events in-between
+    // the strokes. Those are used to update the speed and smudge
+    // filters. We have to do a workaround since we don't have access
+    // to those events. Of course, the start of each stroke can look
+    // different from MyPaint because of this, especially for brushes
+    // with strong speed dynamics.
+
+    if (m_mustEndPreviousStroke) {
+      m_mustEndPreviousStroke = false;
+      // End the previous stroke by telling the brush engine that we
+      // didn't receive any motion events for more than 5 seconds.
+      m_brush->stroke_to(m_surface,
+                         pi1.pos().x(), pi1.pos().y(),
+                         0.0,
+                         10.0);
     }
-    m_mypaintThinksStrokeHasEnded = m_brush->stroke_to(m_surface,
-                                                       pi2.pos().x(), pi2.pos().y(),
-                                                       pi2.pressure(),
-                                                       qreal(m_eventTime.elapsed()) / 1000);
 
-    m_eventTime.restart();
+    m_brush->stroke_to(m_surface,
+                       pi2.pos().x(), pi2.pos().y(),
+                       pi2.pressure(),
+                       qreal(pi2.currentTime() - pi1.currentTime()) / 1000);
 
     // not sure what to do with these...
     KisVector2D end = toKisVector2D(pi2.pos());
diff --git a/krita/plugins/paintops/mypaint/mypaint_paintop.h b/krita/plugins/paintops/mypaint/mypaint_paintop.h
index a715515..8043fe8 100644
--- a/krita/plugins/paintops/mypaint/mypaint_paintop.h
+++ b/krita/plugins/paintops/mypaint/mypaint_paintop.h
@@ -47,8 +47,7 @@ public:
 
 private:
 
-    QTime m_eventTime;
-    bool m_mypaintThinksStrokeHasEnded;
+    bool m_mustEndPreviousStroke;
     MyPaintSurface* m_surface;
     const MyPaintSettings* m_settings;
     MyPaintBrushResource *m_brush;
-- 
1.7.2.3


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