Add sharpen, blur and despeckle image filters

src/calibre/gui2/tweak_book/editor/canvas.py

@@ -177,6 +177,36 @@ class Scale(Command):
         img = canvas.current_image
         return img.scaled(self.width, self.height, transformMode=Qt.SmoothTransformation)
 
+class Sharpen(Command):
+
+    TEXT = _('Sharpen image')
+    FUNC = 'sharpen'
+
+    def __init__(self, sigma, canvas):
+        self.sigma = sigma
+        Command.__init__(self, canvas)
+
+    def __call__(self, canvas):
+        img = canvas.current_image
+        i = qimage_to_magick(img)
+        getattr(i, self.FUNC)(0.0, self.sigma)
+        return magick_to_qimage(i)
+
+class Blur(Sharpen):
+
+    TEXT = _('Blur image')
+    FUNC = 'blur'
+
+class Despeckle(Command):
+
+    TEXT = _('De-speckle image')
+
+    def __call__(self, canvas):
+        img = canvas.current_image
+        i = qimage_to_magick(img)
+        i.despeckle()
+        return magick_to_qimage(i)
+
 class Replace(Command):
 
     ''' Replace the current image with another image. If there is a selection,
@@ -204,7 +234,11 @@ def imageop(func):
             return error_dialog(self, _('No image'), _('No image loaded'), show=True)
         if not self.is_valid:
             return error_dialog(self, _('Invalid image'), _('The current image is not valid'), show=True)
-        return func(self, *args, **kwargs)
+        QApplication.setOverrideCursor(Qt.BusyCursor)
+        try:
+            return func(self, *args, **kwargs)
+        finally:
+            QApplication.restoreOverrideCursor()
     return ans
 
 class Canvas(QWidget):
@@ -329,6 +363,21 @@ class Canvas(QWidget):
         self.undo_stack.push(Scale(width, height, self))
         return True
 
+    @imageop
+    def sharpen_image(self, sigma=3.0):
+        self.undo_stack.push(Sharpen(sigma, self))
+        return True
+
+    @imageop
+    def blur_image(self, sigma=3.0):
+        self.undo_stack.push(Blur(sigma, self))
+        return True
+
+    @imageop
+    def despeckle_image(self):
+        self.undo_stack.push(Despeckle(self))
+        return True
+
     # The selection rectangle {{{
     @property
     def dc_size(self):

src/calibre/gui2/tweak_book/editor/image.py

@@ -11,7 +11,7 @@ from functools import partial
 
 from PyQt4.Qt import (
     QMainWindow, Qt, QApplication, pyqtSignal, QLabel, QIcon, QFormLayout,
-    QDialog, QSpinBox, QCheckBox, QDialogButtonBox, QToolButton, QMenu)
+    QDialog, QSpinBox, QCheckBox, QDialogButtonBox, QToolButton, QMenu, QInputDialog)
 
 from calibre.gui2 import error_dialog
 from calibre.gui2.tweak_book import actions
@@ -244,6 +244,9 @@ class Editor(QMainWindow):
         self.filters_menu = m = QMenu()
         ac.setMenu(m)
         m.addAction(_('Auto-trim image'), self.canvas.autotrim_image)
+        m.addAction(_('Sharpen image'), self.sharpen_image)
+        m.addAction(_('Blur image'), self.blur_image)
+        m.addAction(_('De-speckle image'), self.canvas.despeckle_image)
 
         self.info_bar = b = self.addToolBar(_('Image information bar'))
         self.fmt_label = QLabel('')
@@ -266,6 +269,18 @@ class Editor(QMainWindow):
         if d.exec_() == d.Accepted:
             self.canvas.resize_image(d.width, d.height)
 
+    def sharpen_image(self):
+        val, ok = QInputDialog.getInt(self, _('Sharpen image'), _(
+            'The standard deviation for the Gaussian sharpen operation (higher means more sharpening)'), value=3, min=1, max=20)
+        if ok:
+            self.canvas.sharpen_image(sigma=val)
+
+    def blur_image(self):
+        val, ok = QInputDialog.getInt(self, _('Blur image'), _(
+            'The standard deviation for the Gaussian blur operation (higher means more blurring)'), value=3, min=1, max=20)
+        if ok:
+            self.canvas.blur_image(sigma=val)
+
 def launch_editor(path_to_edit, path_is_raw=False):
     app = QApplication([])
     if path_is_raw:

src/calibre/utils/magick/magick.c

@@ -1154,6 +1154,22 @@ magick_Image_sharpen(magick_Image *self, PyObject *args) {
 }
 // }}}
 
+// Image.blur {{{
+
+static PyObject *
+magick_Image_blur(magick_Image *self, PyObject *args) {
+    double radius, sigma;
+   
+    NULL_CHECK(NULL)
+
+    if (!PyArg_ParseTuple(args, "dd", &radius, &sigma)) return NULL;
+
+    if (!MagickBlurImage(self->wand, radius, sigma)) return magick_set_exception(self->wand);
+
+    Py_RETURN_NONE;
+}
+// }}}
+
 // Image.quantize {{{
 
 static PyObject *
@@ -1431,8 +1447,12 @@ static PyMethodDef magick_Image_methods[] = {
      "sharpen(radius, sigma) \n\n sharpens an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and MagickSharpenImage() selects a suitable radius for you." 
     },
 
+    {"blur", (PyCFunction)magick_Image_blur, METH_VARARGS,
+     "blur(radius, sigma) \n\n blurs an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and MagickBlurImage() selects a suitable radius for you." 
+    },
+
     {"despeckle", (PyCFunction)magick_Image_despeckle, METH_VARARGS,
-     "despeckle() \n\n reduces the speckle noise in an image while perserving the edges of the original image." 
+     "despeckle() \n\n reduces the speckle noise in an image while preserving the edges of the original image." 
     },
 
     {"quantize", (PyCFunction)magick_Image_quantize, METH_VARARGS,