# Copyright (C) 2008, One Laptop per Child # Author: Sayamindu Dasgupta # # 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 St, Fifth Floor, Boston, MA 02110-1301 USA # # From ImageViewer Activity - file ImageView.py import cairo import math from gi.repository import GLib from gi.repository import Gtk from gi.repository import Gdk from gi.repository import GdkPixbuf from gi.repository import GObject from gi.repository import Gio ZOOM_STEP = 0.05 ZOOM_MAX = 10 ZOOM_MIN = 0.05 def pixbuf_from_data(data): stream = Gio.MemoryInputStream.new_from_data(data, None) pixbuf = GdkPixbuf.Pixbuf.new_from_stream(stream, None) return pixbuf def _surface_from_data(data, ctx): pixbuf = pixbuf_from_data(data) surface = ctx.get_target().create_similar( cairo.CONTENT_COLOR_ALPHA, pixbuf.get_width(), pixbuf.get_height()) ctx_surface = cairo.Context(surface) Gdk.cairo_set_source_pixbuf(ctx_surface, pixbuf, 0, 0) ctx_surface.paint() return surface def _rotate_surface(surface, direction): ctx = cairo.Context(surface) new_surface = ctx.get_target().create_similar( cairo.CONTENT_COLOR_ALPHA, surface.get_height(), surface.get_width()) ctx_surface = cairo.Context(new_surface) if direction == 1: ctx_surface.translate(surface.get_height(), 0) else: ctx_surface.translate(0, surface.get_width()) ctx_surface.rotate(math.pi / 2 * direction) ctx_surface.set_source_surface(surface, 0, 0) ctx_surface.paint() return new_surface def _flip_surface(surface): ctx = cairo.Context(surface) new_surface = ctx.get_target().create_similar( cairo.CONTENT_COLOR_ALPHA, surface.get_width(), surface.get_height()) ctx_surface = cairo.Context(new_surface) ctx_surface.rotate(math.pi) ctx_surface.translate(-surface.get_width(), -surface.get_height()) ctx_surface.set_source_surface(surface, 0, 0) ctx_surface.paint() return new_surface class ImageViewer(Gtk.DrawingArea, Gtk.Scrollable): __gtype_name__ = 'ImageViewer' __gproperties__ = { "hscroll-policy": (Gtk.ScrollablePolicy, "hscroll-policy", "hscroll-policy", Gtk.ScrollablePolicy.MINIMUM, GObject.ParamFlags.READWRITE), "hadjustment": (Gtk.Adjustment, "hadjustment", "hadjustment", GObject.ParamFlags.READWRITE), "vscroll-policy": (Gtk.ScrollablePolicy, "hscroll-policy", "hscroll-policy", Gtk.ScrollablePolicy.MINIMUM, GObject.ParamFlags.READWRITE), "vadjustment": (Gtk.Adjustment, "hadjustment", "hadjustment", GObject.ParamFlags.READWRITE), } __gsignals__ = { 'setup-new-surface': (GObject.SignalFlags.RUN_FIRST, GObject.TYPE_NONE, ([])), } def __init__(self): Gtk.DrawingArea.__init__(self) self._data = None self._data_changed = False self._surface = None self._zoom = None self._target_point = None self._anchor_point = None self._in_dragtouch = False self._in_zoomtouch = False self._zoomtouch_scale = 1 self._in_scrolling = False self._scrolling_hid = None self._hadj = None self._vadj = None self._hadj_value_changed_hid = None self._vadj_value_changed_hid = None self.connect('draw', self.__draw_cb) def set_data(self, data): self._data = data self._data_changed = True self.queue_draw() def do_get_property(self, prop): # We don't use the getter but GTK wants it defined as we are # implementing Gtk.Scrollable interface. pass def do_set_property(self, prop, value): # The scrolled window will give us the adjustments. Make a # reference to them and also connect to their value-changed # signal. if prop.name == 'hadjustment': if value is not None: hadj = value self._hadj_value_changed_hid = \ hadj.connect('value-changed', self.__hadj_value_changed_cb) self._hadj = hadj elif prop.name == 'vadjustment': if value is not None: vadj = value self._vadj_value_changed_hid = \ vadj.connect('value-changed', self.__vadj_value_changed_cb) self._vadj = vadj def update_adjustments(self): alloc = self.get_allocation() scaled_width = self._surface.get_width() * self._zoom scaled_height = self._surface.get_height() * self._zoom page_size_x = alloc.width * 1.0 / scaled_width self._hadj.set_lower(0) self._hadj.set_page_size(page_size_x) self._hadj.set_upper(1.0) self._hadj.set_step_increment(0.1) self._hadj.set_page_increment(0.5) page_size_y = alloc.height * 1.0 / scaled_height self._vadj.set_lower(0) self._vadj.set_page_size(page_size_y) self._vadj.set_upper(1.0) self._vadj.set_step_increment(0.1) self._vadj.set_page_increment(0.5) anchor_scaled = (self._anchor_point[0] * self._zoom, self._anchor_point[1] * self._zoom) # This vector is the top left coordinate of the scaled image. scaled_image_topleft = (self._target_point[0] - anchor_scaled[0], self._target_point[1] - anchor_scaled[1]) max_topleft = (scaled_width - alloc.width, scaled_height - alloc.height) max_value = (1.0 - page_size_x, 1.0 - page_size_y) # This two linear functions map the topleft corner of the # image to the value each adjustment. if max_topleft[0] != 0: self._hadj.disconnect(self._hadj_value_changed_hid) self._hadj.set_value(-1 * max_value[0] * scaled_image_topleft[0] / max_topleft[0]) self._hadj_value_changed_hid = \ self._hadj.connect('value-changed', self.__hadj_value_changed_cb) if max_topleft[1] != 0: self._vadj.disconnect(self._vadj_value_changed_hid) self._vadj.set_value(-1 * max_value[1] * scaled_image_topleft[1] / max_topleft[1]) self._vadj_value_changed_hid = \ self._vadj.connect('value-changed', self.__vadj_value_changed_cb) def _stop_scrolling(self): self._in_scrolling = False self.queue_draw() return False def _start_scrolling(self): if not self._in_scrolling: self._in_scrolling = True # Add or update a timer after which the in_scrolling flag will # be set to False. This is to perform a faster drawing while # scrolling. if self._scrolling_hid is not None: GLib.source_remove(self._scrolling_hid) self._scrolling_hid = GLib.timeout_add(200, self._stop_scrolling) def __hadj_value_changed_cb(self, adj): alloc = self.get_allocation() scaled_width = self._surface.get_width() * self._zoom anchor_scaled_x = self._anchor_point[0] * self._zoom scaled_image_left = self._target_point[0] - anchor_scaled_x max_left = scaled_width - alloc.width max_value = 1.0 - adj.get_page_size() new_left = -1 * max_left * adj.get_value() / max_value delta_x = scaled_image_left - new_left self._anchor_point = (self._anchor_point[0] + delta_x, self._anchor_point[1]) self._start_scrolling() self.queue_draw() def __vadj_value_changed_cb(self, adj): alloc = self.get_allocation() scaled_height = self._surface.get_height() * self._zoom anchor_scaled_y = self._anchor_point[1] * self._zoom scaled_image_top = self._target_point[1] - anchor_scaled_y max_top = scaled_height - alloc.height max_value = 1.0 - adj.get_page_size() new_top = -1 * max_top * adj.get_value() / max_value delta_y = scaled_image_top - new_top self._anchor_point = (self._anchor_point[0], self._anchor_point[1] + delta_y) self._start_scrolling() self.queue_draw() def _center_target_point(self): alloc = self.get_allocation() self._target_point = (alloc.width / 2, alloc.height / 2) def _center_anchor_point(self): self._anchor_point = (self._surface.get_width() / 2, self._surface.get_height() / 2) def _center_if_small(self): # If at the current size the image surface is smaller than the # available space, center it on the canvas. alloc = self.get_allocation() scaled_width = self._surface.get_width() * self._zoom scaled_height = self._surface.get_height() * self._zoom if alloc.width >= scaled_width and alloc.height >= scaled_height: self._center_target_point() self._center_anchor_point() self.queue_draw() def set_zoom(self, zoom): if zoom < ZOOM_MIN or zoom > ZOOM_MAX: return self._zoom = zoom self.queue_draw() def get_zoom(self): return self._zoom def can_zoom_in(self): return self._zoom + ZOOM_STEP < ZOOM_MAX self.update_adjustments() def can_zoom_out(self): return self._zoom - ZOOM_STEP > ZOOM_MIN self.update_adjustments() def zoom_in(self): if not self.can_zoom_in(): return self._zoom += ZOOM_STEP self.update_adjustments() self.queue_draw() def zoom_out(self): if not self.can_zoom_out(): return self._zoom -= ZOOM_MIN self._center_if_small() self.update_adjustments() self.queue_draw() def zoom_to_fit(self): # This tries to figure out a best fit model # We show it in a fit to screen way alloc = self.get_allocation() surface_width = self._surface.get_width() surface_height = self._surface.get_height() self._zoom = min(alloc.width * 1.0 / surface_width, alloc.height * 1.0 / surface_height) self._center_target_point() self._center_anchor_point() self.update_adjustments() self.queue_draw() def zoom_to_width(self): alloc = self.get_allocation() surface_width = self._surface.get_width() self._zoom = alloc.width * 1.0 / surface_width self._center_target_point() self._center_anchor_point() self.update_adjustments() self.queue_draw() def zoom_original(self): self._zoom = 1 self._center_if_small() self.update_adjustments() self.queue_draw() def _move_anchor_to_target(self, prev_target_point): # Calculate the new anchor point, move it from the previous # target to the new one. prev_anchor_scaled = (self._anchor_point[0] * self._zoom, self._anchor_point[1] * self._zoom) # This vector is the top left coordinate of the scaled image. scaled_image_topleft = (prev_target_point[0] - prev_anchor_scaled[0], prev_target_point[1] - prev_anchor_scaled[1]) anchor_scaled = (self._target_point[0] - scaled_image_topleft[0], self._target_point[1] - scaled_image_topleft[1]) self._anchor_point = (int(anchor_scaled[0] * 1.0 / self._zoom), int(anchor_scaled[1] * 1.0 / self._zoom)) def start_dragtouch(self, coords): self._in_dragtouch = True prev_target_point = self._target_point # Set target point to the relative coordinates of this view. self._target_point = (coords[1], coords[2]) self._move_anchor_to_target(prev_target_point) self.queue_draw() def update_dragtouch(self, coords): # Drag touch will be replaced by zoom touch if another finger # is placed over the display. When the user finishes zoom # touch, it will probably remove one finger after the other, # and this method will be called. In that probable case, we # need to start drag touch again. if not self._in_dragtouch: self.start_dragtouch(coords) return self._target_point = (coords[1], coords[2]) self.update_adjustments() self.queue_draw() def finish_dragtouch(self, coords): self._in_dragtouch = False self._center_if_small() self.update_adjustments() def start_zoomtouch(self, center): self._in_zoomtouch = True self._zoomtouch_scale = 1 # Zoom touch replaces drag touch. self._in_dragtouch = False prev_target_point = self._target_point # Set target point to the relative coordinates of this view. alloc = self.get_allocation() self._target_point = (center[1] - alloc.x, center[2] - alloc.y) self._move_anchor_to_target(prev_target_point) self.queue_draw() def update_zoomtouch(self, center, scale): self._zoomtouch_scale = scale # Set target point to the relative coordinates of this view. alloc = self.get_allocation() self._target_point = (center[1] - alloc.x, center[2] - alloc.y) self.queue_draw() def finish_zoomtouch(self): self._in_zoomtouch = False # Apply zoom self._zoom = self._zoom * self._zoomtouch_scale self._zoomtouch_scale = 1 # Restrict zoom values if self._zoom < ZOOM_MIN: self._zoom = ZOOM_MIN elif self._zoom > ZOOM_MAX: self._zoom = ZOOM_MAX self._center_if_small() self.update_adjustments() self.queue_draw() def set_rotate(self, rotate): if rotate == 0: return elif rotate in [1, -3]: self._surface = _rotate_surface(self._surface, 1) elif rotate in [-1, 3]: self._surface = _rotate_surface(self._surface, -1) else: self._surface = _flip_surface(self._surface) if rotate > 0: for i in range(rotate): self._anchor_point = ( self._surface.get_width() - self._anchor_point[1], self._anchor_point[0]) if rotate < 0: for i in range(-rotate): self._anchor_point = ( self._anchor_point[1], self._surface.get_height() - self._anchor_point[0]) self.update_adjustments() self.queue_draw() def rotate_anticlockwise(self): self._surface = _rotate_surface(self._surface, -1) # Recalculate the anchor point to make it relative to the new # top left corner. self._anchor_point = ( self._anchor_point[1], self._surface.get_height() - self._anchor_point[0]) self.update_adjustments() self.queue_draw() def rotate_clockwise(self): self._surface = _rotate_surface(self._surface, 1) # Recalculate the anchor point to make it relative to the new # top left corner. self._anchor_point = ( self._surface.get_width() - self._anchor_point[1], self._anchor_point[0]) self.update_adjustments() self.queue_draw() def __draw_cb(self, widget, ctx): # If the image surface is not set, it reads it from the data If the # data is not set yet, it just returns. if self._surface is None or self._data_changed: if self._data is None: return self._surface = _surface_from_data(self._data, ctx) self._data_changed = False self.emit('setup-new-surface') if self._zoom is None: self.zoom_to_width() # If no target point was set via pinch-to-zoom, default to the # center of the screen. if self._target_point is None: self._center_target_point() # If no anchor point was set via pinch-to-zoom, default to the # center of the surface. if self._anchor_point is None: self._center_anchor_point() self.update_adjustments() ctx.translate(*self._target_point) zoom_absolute = self._zoom * self._zoomtouch_scale ctx.scale(zoom_absolute, zoom_absolute) ctx.translate(self._anchor_point[0] * -1, self._anchor_point[1] * -1) ctx.set_source_surface(self._surface, 0, 0) # Perform faster draw if the view is zooming or scrolling via # mouse or touch. if self._in_zoomtouch or self._in_dragtouch or self._in_scrolling: ctx.get_source().set_filter(cairo.FILTER_NEAREST) ctx.paint()