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Implement Uniscribe RenderText for Windows.
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Follow the I18N recommendations for BiDi text editing.
Visual cursor movement and logical selection over BiDi text.
Cleanup some common RenderText code and interfaces.
Fixup TextfieldExample for views_examples.

Known issues:
Word breaking is not well implemented.
Font sizes and vertical alignments are slightly off.
Text styles break runs (colors can affect glyph shaping).
Composition/selection ranges aren't stylized.

BUG=90426
TEST=--use-pure-views text editing

Review URL: http://codereview.chromium.org/7458014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@98785 0039d316-1c4b-4281-b951-d872f2087c98
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msw@chromium.org committed Aug 30, 2011
1 parent 139212d commit 0d71760
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Showing 8 changed files with 892 additions and 94 deletions.
142 changes: 98 additions & 44 deletions ui/gfx/render_text.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -164,14 +164,8 @@ void RenderText::SetText(const string16& text) {
cached_bounds_and_offset_valid_ = false;
}

void RenderText::SetSelectionModel(const SelectionModel& sel) {
size_t start = sel.selection_start();
size_t end = sel.selection_end();
selection_model_.set_selection_start(std::min(start, text().length()));
selection_model_.set_selection_end(std::min(end, text().length()));
selection_model_.set_caret_pos(std::min(sel.caret_pos(), text().length()));
selection_model_.set_caret_placement(sel.caret_placement());

void RenderText::ToggleInsertMode() {
insert_mode_ = !insert_mode_;
cached_bounds_and_offset_valid_ = false;
}

Expand All @@ -184,13 +178,8 @@ size_t RenderText::GetCursorPosition() const {
return selection_model_.selection_end();
}

void RenderText::SetCursorPosition(const size_t position) {
SelectionModel sel(selection_model());
sel.set_selection_start(position);
sel.set_selection_end(position);
sel.set_caret_pos(GetIndexOfPreviousGrapheme(position));
sel.set_caret_placement(SelectionModel::TRAILING);
SetSelectionModel(sel);
void RenderText::SetCursorPosition(size_t position) {
MoveCursorTo(position, false);
}

void RenderText::MoveCursorLeft(BreakType break_type, bool select) {
Expand Down Expand Up @@ -237,9 +226,26 @@ void RenderText::MoveCursorRight(BreakType break_type, bool select) {
MoveCursorTo(position);
}

bool RenderText::MoveCursorTo(const SelectionModel& selection) {
bool changed = !selection.Equals(selection_model_);
SetSelectionModel(selection);
bool RenderText::MoveCursorTo(const SelectionModel& selection_model) {
SelectionModel sel(selection_model);
size_t text_length = text().length();
// Enforce valid selection model components.
if (sel.selection_start() > text_length)
sel.set_selection_start(text_length);
if (sel.selection_end() > text_length)
sel.set_selection_end(text_length);
// The current model only supports caret positions at valid character indices.
if (text_length == 0) {
sel.set_caret_pos(0);
sel.set_caret_placement(SelectionModel::LEADING);
} else if (sel.caret_pos() >= text_length) {
SelectionModel end = GetTextDirection() == base::i18n::RIGHT_TO_LEFT ?
LeftEndSelectionModel() : RightEndSelectionModel();
sel.set_caret_pos(end.caret_pos());
sel.set_caret_placement(end.caret_placement());
}
bool changed = !sel.Equals(selection_model_);
SetSelectionModel(sel);
return changed;
}

Expand All @@ -251,6 +257,8 @@ bool RenderText::MoveCursorTo(const Point& point, bool select) {
}

bool RenderText::IsPointInSelection(const Point& point) {
if (EmptySelection())
return false;
// TODO(xji): should this check whether the point is inside the visual
// selection bounds? In case of "abcFED", if "ED" is selected, |point| points
// to the right half of 'c', is the point in selection?
Expand All @@ -265,8 +273,8 @@ void RenderText::ClearSelection() {
}

void RenderText::SelectAll() {
SelectionModel sel(0, text().length(),
text().length(), SelectionModel::LEADING);
SelectionModel sel(RightEndSelectionModel());
sel.set_selection_start(LeftEndSelectionModel().selection_start());
SetSelectionModel(sel);
}

Expand Down Expand Up @@ -308,12 +316,8 @@ void RenderText::SelectWord() {
break;
}

SelectionModel sel(selection_model());
sel.set_selection_start(selection_start);
sel.set_selection_end(cursor_position);
sel.set_caret_pos(GetIndexOfPreviousGrapheme(cursor_position));
sel.set_caret_placement(SelectionModel::TRAILING);
SetSelectionModel(sel);
MoveCursorTo(selection_start, false);
MoveCursorTo(cursor_position, true);
}

const ui::Range& RenderText::GetCompositionRange() const {
Expand Down Expand Up @@ -350,8 +354,8 @@ void RenderText::ApplyDefaultStyle() {
}

base::i18n::TextDirection RenderText::GetTextDirection() const {
// TODO(msw): Bidi implementation, intended to replace the functionality added
// in crrev.com/91881 (discussed in codereview.chromium.org/7324011).
if (base::i18n::IsRTL())
return base::i18n::RIGHT_TO_LEFT;
return base::i18n::LEFT_TO_RIGHT;
}

Expand Down Expand Up @@ -443,20 +447,6 @@ SelectionModel RenderText::FindCursorPosition(const Point& point) {
return SelectionModel(left_pos);
}

std::vector<Rect> RenderText::GetSubstringBounds(size_t from, size_t to) {
size_t start = std::min(from, to);
size_t end = std::max(from, to);
const Font& font = default_style_.font;
int start_x = font.GetStringWidth(text().substr(0, start));
int end_x = font.GetStringWidth(text().substr(0, end));
Rect rect(start_x, 0, end_x - start_x, font.GetHeight());
rect.Offset(display_rect_.origin());
rect.Offset(GetUpdatedDisplayOffset());
// Center the rect vertically in |display_rect_|.
rect.Offset(Point(0, (display_rect_.height() - rect.height()) / 2));
return std::vector<Rect>(1, rect);
}

Rect RenderText::GetCursorBounds(const SelectionModel& selection,
bool insert_mode) {
size_t from = selection.selection_end();
Expand Down Expand Up @@ -549,9 +539,35 @@ SelectionModel RenderText::GetRightSelectionModel(const SelectionModel& current,
return SelectionModel(pos, pos, SelectionModel::LEADING);
}

SelectionModel RenderText::LeftEndSelectionModel() {
return SelectionModel(0, 0, SelectionModel::LEADING);
}

SelectionModel RenderText::RightEndSelectionModel() {
size_t cursor = text().length();
size_t caret_pos = GetIndexOfPreviousGrapheme(cursor);
SelectionModel::CaretPlacement placement = (caret_pos == cursor) ?
SelectionModel::LEADING : SelectionModel::TRAILING;
return SelectionModel(cursor, caret_pos, placement);
}

size_t RenderText::GetIndexOfPreviousGrapheme(size_t position) {
// TODO(msw): Handle complex script.
return std::max(static_cast<int>(position - 1), static_cast<int>(0));
return std::max(static_cast<long>(position - 1), static_cast<long>(0));
}

std::vector<Rect> RenderText::GetSubstringBounds(size_t from, size_t to) {
size_t start = std::min(from, to);
size_t end = std::max(from, to);
const Font& font = default_style_.font;
int start_x = font.GetStringWidth(text().substr(0, start));
int end_x = font.GetStringWidth(text().substr(0, end));
Rect rect(start_x, 0, end_x - start_x, font.GetHeight());
rect.Offset(display_rect_.origin());
rect.Offset(GetUpdatedDisplayOffset());
// Center the rect vertically in |display_rect_|.
rect.Offset(Point(0, (display_rect_.height() - rect.height()) / 2));
return std::vector<Rect>(1, rect);
}

void RenderText::ApplyCompositionAndSelectionStyles(
Expand All @@ -576,6 +592,45 @@ void RenderText::ApplyCompositionAndSelectionStyles(
}
}

Point RenderText::ToTextPoint(const Point& point) {
Point p(point.Subtract(display_rect().origin()));
p = p.Subtract(GetUpdatedDisplayOffset());
if (base::i18n::IsRTL())
p.Offset(GetStringWidth() - display_rect().width() + 1, 0);
return p;
}

Point RenderText::ToViewPoint(const Point& point) {
Point p(point.Add(display_rect().origin()));
p = p.Add(GetUpdatedDisplayOffset());
if (base::i18n::IsRTL())
p.Offset(display_rect().width() - GetStringWidth() - 1, 0);
return p;
}

void RenderText::SetSelectionModel(const SelectionModel& selection_model) {
DCHECK_LE(selection_model.selection_start(), text().length());
selection_model_.set_selection_start(selection_model.selection_start());
DCHECK_LE(selection_model.selection_end(), text().length());
selection_model_.set_selection_end(selection_model.selection_end());
DCHECK_LT(selection_model.caret_pos(),
std::max(text().length(), static_cast<size_t>(1)));
selection_model_.set_caret_pos(selection_model.caret_pos());
selection_model_.set_caret_placement(selection_model.caret_placement());

cached_bounds_and_offset_valid_ = false;
}

void RenderText::MoveCursorTo(size_t position, bool select) {
size_t cursor = std::min(position, text().length());
size_t caret_pos = GetIndexOfPreviousGrapheme(cursor);
SelectionModel::CaretPlacement placement = (caret_pos == cursor) ?
SelectionModel::LEADING : SelectionModel::TRAILING;
size_t selection_start = select ? GetSelectionStart() : cursor;
SelectionModel sel(selection_start, cursor, caret_pos, placement);
SetSelectionModel(sel);
}

bool RenderText::IsPositionAtWordSelectionBoundary(size_t pos) {
return pos == 0 || (u_isalnum(text()[pos - 1]) && !u_isalnum(text()[pos])) ||
(!u_isalnum(text()[pos - 1]) && u_isalnum(text()[pos]));
Expand All @@ -589,7 +644,6 @@ void RenderText::UpdateCachedBoundsAndOffset() {
// function will set |cursor_bounds_| and |display_offset_| to correct values.
cached_bounds_and_offset_valid_ = true;
cursor_bounds_ = GetCursorBounds(selection_model_, insert_mode_);
cursor_bounds_.set_width(std::max(cursor_bounds_.width(), 1));
// Update |display_offset_| to ensure the current cursor is visible.
int display_width = display_rect_.width();
int string_width = GetStringWidth();
Expand Down
52 changes: 34 additions & 18 deletions ui/gfx/render_text.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -154,13 +154,12 @@ class UI_EXPORT RenderText {
virtual void SetText(const string16& text);

const SelectionModel& selection_model() const { return selection_model_; }
void SetSelectionModel(const SelectionModel& sel);

bool cursor_visible() const { return cursor_visible_; }
void set_cursor_visible(bool visible) { cursor_visible_ = visible; }

bool insert_mode() const { return insert_mode_; }
void toggle_insert_mode() { insert_mode_ = !insert_mode_; }
void ToggleInsertMode();

bool focused() const { return focused_; }
void set_focused(bool focused) { focused_ = focused; }
Expand All @@ -176,24 +175,26 @@ class UI_EXPORT RenderText {
// edits take place, and doesn't necessarily correspond to
// SelectionModel::caret_pos.
size_t GetCursorPosition() const;
void SetCursorPosition(const size_t position);
void SetCursorPosition(size_t position);

void SetCaretPlacement(SelectionModel::CaretPlacement placement) {
selection_model_.set_caret_placement(placement);
}

// Moves the cursor left or right. Cursor movement is visual, meaning that
// left and right are relative to screen, not the directionality of the text.
// If |select| is false, the selection range is emptied at the new position.
// If |select| is false, the selection start is moved to the same position.
void MoveCursorLeft(BreakType break_type, bool select);
void MoveCursorRight(BreakType break_type, bool select);

// Set the selection_model_ to the value of |selection|.
// The selection model components are modified if invalid.
// Returns true if the cursor position or selection range changed.
bool MoveCursorTo(const SelectionModel& selection);
bool MoveCursorTo(const SelectionModel& selection_model);

// Move the cursor to the position associated with the clicked point.
// If |select| is false, the selection range is emptied at the new position.
// If |select| is false, the selection start is moved to the same position.
// Returns true if the cursor position or selection range changed.
bool MoveCursorTo(const Point& point, bool select);

size_t GetSelectionStart() const {
Expand Down Expand Up @@ -236,13 +237,6 @@ class UI_EXPORT RenderText {
// Gets the SelectionModel from a visual point in local coordinates.
virtual SelectionModel FindCursorPosition(const Point& point);

// Get the visual bounds containing the logical substring within |from| to
// |to|. These bounds could be visually discontinuous if the substring is
// split by a LTR/RTL level change. These bounds are in local coordinates, but
// may be outside the visible region if the text is longer than the textfield.
// Subsequent text, cursor, or bounds changes may invalidate returned values.
virtual std::vector<Rect> GetSubstringBounds(size_t from, size_t to);

// Get the visual bounds of a cursor at |selection|. These bounds typically
// represent a vertical line, but if |insert_mode| is true they contain the
// bounds of the associated glyph. These bounds are in local coordinates, but
Expand Down Expand Up @@ -274,13 +268,31 @@ class UI_EXPORT RenderText {
virtual SelectionModel GetRightSelectionModel(const SelectionModel& current,
BreakType break_type);

// Get the SelectionModels corresponding to visual text ends.
// The returned value represents a cursor/caret position without a selection.
virtual SelectionModel LeftEndSelectionModel();
virtual SelectionModel RightEndSelectionModel();

// Get the logical index of the grapheme preceeding the argument |position|.
virtual size_t GetIndexOfPreviousGrapheme(size_t position);

// Get the visual bounds containing the logical substring within |from| to
// |to|. These bounds could be visually discontinuous if the substring is
// split by a LTR/RTL level change. These bounds are in local coordinates, but
// may be outside the visible region if the text is longer than the textfield.
// Subsequent text, cursor, or bounds changes may invalidate returned values.
// TODO(msw) Re-evaluate this function's necessity and signature.
virtual std::vector<Rect> GetSubstringBounds(size_t from, size_t to);

// Apply composition style (underline) to composition range and selection
// style (foreground) to selection range.
void ApplyCompositionAndSelectionStyles(StyleRanges* style_ranges) const;

// Convert points from the text space to the view space and back.
// Handles the display area, display offset, and the application LTR/RTL mode.
Point ToTextPoint(const Point& point);
Point ToViewPoint(const Point& point);

private:
friend class RenderTextTest;

Expand All @@ -289,8 +301,13 @@ class UI_EXPORT RenderText {
FRIEND_TEST_ALL_PREFIXES(RenderTextTest, ApplyStyleRange);
FRIEND_TEST_ALL_PREFIXES(RenderTextTest, StyleRangesAdjust);

// Clear out |style_ranges_|.
void ClearStyleRanges();
// Sets the selection model, the argument is assumed to be valid.
void SetSelectionModel(const SelectionModel& selection_model);

// Set the cursor to |position|, with the caret trailing the previous
// grapheme, or if there is no previous grapheme, leading the cursor position.
// If |select| is false, the selection start is moved to the same position.
void MoveCursorTo(size_t position, bool select);

bool IsPositionAtWordSelectionBoundary(size_t pos);

Expand Down Expand Up @@ -328,9 +345,8 @@ class UI_EXPORT RenderText {
// Get this point with GetUpdatedDisplayOffset (or risk using a stale value).
Point display_offset_;

// The cached bounds and offset are invalidated by operations such as
// SetCursorPosition, SetSelectionModel, Font related style change, and other
// operations that adjust the visible text bounds.
// The cached bounds and offset are invalidated by changes to the cursor,
// selection, font, and other operations that adjust the visible text bounds.
bool cached_bounds_and_offset_valid_;

DISALLOW_COPY_AND_ASSIGN(RenderText);
Expand Down
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