1 files changed, 140 insertions, 0 deletions
diff --git a/krita/plugins/paintops/defaultpaintops/kis_eraseop.cc b/krita/plugins/paintops/defaultpaintops/kis_eraseop.cc
new file mode 100644
index 00000000..4fe46af2
--- /dev/null
+++ b/krita/plugins/paintops/defaultpaintops/kis_eraseop.cc
@@ -0,0 +1,140 @@
+/*
+ *  Copyright (c) 2002 Patrick Julien <freak@codepimps.org>
+ *  Copyright (c) 2004 Boudewijn Rempt <boud@valdyas.org>
+ *  Copyright (c) 2004 Clarence Dang <dang@kde.org>
+ *  Copyright (c) 2004 Adrian Page <adrian@pagenet.plus.com>
+ *  Copyright (c) 2004 Cyrille Berger <cberger@cberger.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <qrect.h>
+
+#include <kdebug.h>
+
+#include "kis_brush.h"
+#include "kis_global.h"
+#include "kis_paint_device.h"
+#include "kis_layer.h"
+#include "kis_painter.h"
+#include "kis_types.h"
+#include "kis_paintop.h"
+#include "kis_iterators_pixel.h"
+#include "kis_colorspace.h"
+#include "kis_selection.h"
+#include "kis_eraseop.h"
+
+KisPaintOp * KisEraseOpFactory::createOp(const KisPaintOpSettings */*settings*/, KisPainter * painter)
+{
+    KisPaintOp * op = new KisEraseOp(painter);
+    Q_CHECK_PTR(op);
+    return op;
+}
+
+
+KisEraseOp::KisEraseOp(KisPainter * painter)
+    : super(painter)
+{
+}
+
+KisEraseOp::~KisEraseOp()
+{
+}
+
+void KisEraseOp::paintAt(const KisPoint &pos, const KisPaintInformation& info)
+{
+// Erasing is traditionally in paint applications one of two things:
+// either it is painting in the 'background' color, or it is replacing
+// all pixels with transparent (black?) pixels.
+//
+// That's what this paint op does for now; however, anyone who has
+// ever worked with paper and soft pencils knows that a sharp piece of
+// eraser rubber is a pretty useful too for making sharp to fuzzy lines
+// in the graphite layer, or equally useful: for smudging skin tones.
+//
+// A smudge tool for Krita is in the making, but when working with
+// a tablet, the eraser tip should be at least as functional as a rubber eraser.
+// That means that only after repeated or forceful application should all the
+// 'paint' or 'graphite' be removed from the surface -- a kind of pressure
+// sensitive, incremental smudge.
+//
+// And there should be an option to not have the eraser work on certain
+// kinds of material. Layers are just a hack for this; putting your ink work
+// in one layer and your pencil in another is not the same as really working
+// with the combination.
+
+    if (!m_painter) return;
+
+    KisPaintDeviceSP device = m_painter->device();
+    if (!device) return;
+
+    KisBrush *brush = m_painter->brush();
+    if (! brush->canPaintFor(info) )
+        return;
+    KisPoint hotSpot = brush->hotSpot(info);
+    KisPoint pt = pos - hotSpot;
+
+    Q_INT32 destX;
+    double xFraction;
+    Q_INT32 destY;
+    double yFraction;
+
+    splitCoordinate(pt.x(), &destX, &xFraction);
+    splitCoordinate(pt.y(), &destY, &yFraction);
+
+    KisAlphaMaskSP mask = brush->mask(info, xFraction, yFraction);
+
+    KisPaintDeviceSP dab = new KisPaintDevice(device->colorSpace(), "erase op dab");
+    Q_CHECK_PTR(dab);
+
+    Q_INT32 maskWidth = mask->width();
+    Q_INT32 maskHeight = mask->height();
+
+    QRect dstRect;
+
+    KisRectIteratorPixel it = dab->createRectIterator(0, 0, maskWidth, maskHeight, true);
+    KisColorSpace* cs = dab->colorSpace();
+    while (!it.isDone()) {
+        cs->setAlpha(it.rawData(), Q_UINT8_MAX - mask->alphaAt(it.x(), it.y()), 1);
+        ++it;
+    }
+
+    QRect dabRect = QRect(0, 0, maskWidth, maskHeight);
+    dstRect = QRect(destX, destY, dabRect.width(), dabRect.height());
+
+    KisImage * image = device->image();
+
+    if (image != 0) {
+        dstRect &= image->bounds();
+    }
+
+    if (dstRect.isNull() || dstRect.isEmpty() || !dstRect.isValid()) return;
+
+    Q_INT32 sx = dstRect.x() - destX;
+    Q_INT32 sy = dstRect.y() - destY;
+    Q_INT32 sw = dstRect.width();
+    Q_INT32 sh = dstRect.height();
+
+    if (m_source->hasSelection()) {
+        m_painter->bltSelection(dstRect.x(), dstRect.y(), COMPOSITE_ERASE, dab.data(),
+                                m_source->selection(), m_painter->opacity(), sx, sy, sw, sh);
+    }
+    else {
+        m_painter->bitBlt(dstRect.x(), dstRect.y(), COMPOSITE_ERASE, dab.data(), m_painter->opacity(), sx, sy, sw, sh);
+    }
+
+    m_painter->addDirtyRect(dstRect);
+}
+