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Drawing: fix glyphs at top/bottom possibly truncated
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This was somehow prevented by using setHidePartialGlyphs(),
which was removed by 7e6e7c6 as it felt a bit odd.
Fix this issue in a hopefully better way by using more
generically the alternative larger clip (previously added
in 6546ef9 for inline-block elements).
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@poire-z
poire-z committed Apr 6, 2022
1 parent 756ae3c commit 495bd5b
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Showing 2 changed files with 59 additions and 26 deletions.
60 changes: 35 additions & 25 deletions crengine/src/lvdocview.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1943,14 +1943,14 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
if (!pageRect)
pageRect = &fullRect;
// drawbuf->setHidePartialGlyphs(getViewMode() == DVM_PAGES); // (is always true)
// setHidePartialGlyphs() was added to "fix partial glyph drawing for small interline spaces
// (<100%) in page mode", but it's not really clear what it is supposed to fix. Moreover,
// while its implementation for top of glyph is understandable (clip, if less of 1/2 original
// height remain, don't draw the glyph), what it does on the bottom is less (if just remove
// the clip and allow drawing the full glyph below the bottom clip!).
// It just feels best to not use it, and just have glyphs all truncated similarly along
// the line of the clip (instead of having a mix of glyphs cut and glyphs absent)
// setHidePartialGlyphs() was added to allow drawing parts of glyphs outside the
// clip (which can happen when small interline space), but its implementation is
// a bit weird (at top: if less of 1/2 original height remain, don't draw the glyph;
// at bottom: removethe clip and allow drawing the full glyph), and it feels this
// is not the right way to solve this issue. So we don't use it.
drawbuf->setHidePartialGlyphs(false);
// We'll solve this issue another way: by using an alternative larger clip when drawing
// line boxes fully contained into the page: draw_extra_info.content_overflow_clip below.

// Clip, for normal content drawing: we use the computed pageRect, and the page.height
// made from page splitting (that we have to enforce to not get painted some content
Expand All @@ -1974,14 +1974,22 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
draw_extra_info.is_left_page = false;
draw_extra_info.is_right_page = false;
draw_extra_info.draw_body_background = true;
draw_extra_info.body_background_clip.top = headerHeight;
draw_extra_info.body_background_clip.bottom = fullRect.bottom;
draw_extra_info.body_background_clip.left = fullRect.left;
draw_extra_info.body_background_clip.right = fullRect.right;
draw_extra_info.content_overflow_clip.top = headerHeight;
draw_extra_info.body_background_clip.top = headerHeight;
draw_extra_info.body_background_clip.bottom = fullRect.bottom;
draw_extra_info.body_background_clip.left = fullRect.left;
draw_extra_info.body_background_clip.right = fullRect.right;
// The above regular "clip" will be used to decide which lines of a paragraph
// (possibly spanning multiple pages) will have to be drawn into this page.
// For such lines fully contained into the regular clip, we will extend (in lvtextfm.cpp)
// the clip so their tall glyphs, possibly overflowing the line box will, not get truncated.
// We allow such glyphs to go into the top margin, but not into the header, and
// allow them to go into the bottom margin, but not into any bottom footnotes area.
// (If header, we could add 3px to not overflow into the progress bar and chapter marks,
// but this would add some empty stripe that is more noticable that occasional overlaps.)
draw_extra_info.content_overflow_clip.top = headerHeight;
draw_extra_info.content_overflow_clip.bottom = fullRect.bottom; // will be reduced if footnotes
draw_extra_info.content_overflow_clip.left = fullRect.left;
draw_extra_info.content_overflow_clip.right = fullRect.right;
draw_extra_info.content_overflow_clip.left = fullRect.left;
draw_extra_info.content_overflow_clip.right = fullRect.right;

if (hasTwoVisiblePages) {
// Don't trust pageRects and their tweaked middle margin
Expand All @@ -1996,15 +2004,15 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
clip.right = middle_x;
draw_extra_info.is_left_page = true;
}
draw_extra_info.body_background_clip.left = clip.left;
draw_extra_info.body_background_clip.right = clip.right;
draw_extra_info.body_background_clip.left = clip.left;
draw_extra_info.body_background_clip.right = clip.right;
if ( !isRightPage && isLastPage ) {
// Left page is last page: have any background
// drawn also on the right blank area
draw_extra_info.body_background_clip.right = fullRect.right;
draw_extra_info.body_background_clip.right = fullRect.right;
}
draw_extra_info.content_overflow_clip.left = clip.left;
draw_extra_info.content_overflow_clip.right = clip.right;
draw_extra_info.content_overflow_clip.left = clip.left;
draw_extra_info.content_overflow_clip.right = clip.right;
}

if (page.flags & RN_PAGE_TYPE_COVER)
Expand Down Expand Up @@ -2078,13 +2086,12 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
// If we have footnotes that we'll put at bottom of page, make sure we
// clip above them (tall inline-block content, even if split across pages,
// could have their content painted over the footnotes)
bool has_footnotes = false;
bool has_footnotes = page.footnotes.length() > 0;
#define FOOTNOTE_MARGIN_REM 1 // as in lvpagesplitter.cpp
int footnote_margin = FOOTNOTE_MARGIN_REM * m_font_size;
int footnotes_height = 0;
for (int fn = 0; fn < page.footnotes.length(); fn++) {
footnotes_height += page.footnotes[fn].height;
has_footnotes = true;
}
if ( has_footnotes) {
// We'll be drawing a separator at 2/3 in the footnote margin.
Expand Down Expand Up @@ -2112,15 +2119,19 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
// Draw footnotes at the bottom of page (put any remaining blank space above them)
int fny = clip.top + (page.height ? page.height + footnote_margin
: footnote_margin);
if (footnotes_height > 0) {
if ( has_footnotes) {
int h_avail = m_dy - getPageHeaderHeight()
- m_pageMargins.top - m_pageMargins.bottom
- height - footnote_margin;
fny += h_avail - footnotes_height; // put empty space before first footnote
draw_extra_info.draw_body_background = false;
// We'll be drawing a separator at 2/3 in the footnote margin.
// Allow over-painting up to it in this footnote margin (so any glyph head
// overflowing the line box get less chances to be truncated.
draw_extra_info.content_overflow_clip.top = fny - footnote_margin * 1/3 + 1;
draw_extra_info.content_overflow_clip.bottom = fullRect.bottom;
}
int fy = fny;
bool footnoteDrawed = false;
for (int fn = 0; fn < page.footnotes.length(); fn++) {
int fstart = page.footnotes[fn].start;
int fheight = page.footnotes[fn].height;
Expand All @@ -2137,10 +2148,9 @@ void LVDocView::drawPageTo(LVDrawBuf * drawbuf, LVRendPageInfo & page,
-fstart, // doc_y
m_dy, // page_height
&m_markRanges);
footnoteDrawed = true;
fy += fheight;
}
if (footnoteDrawed) { // && page.height
if ( has_footnotes) {
// Draw a small horizontal line as a separator inside
// the margin between text and footnotes
fny -= footnote_margin * 1/3;
Expand Down
25 changes: 24 additions & 1 deletion crengine/src/lvtextfm.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4784,6 +4784,7 @@ void LFormattedText::Draw( LVDrawBuf * buf, int x, int y, ldomMarkedRangeList *
buf->GetClipRect( &clip );
const lChar32 * str;
int line_y = y;
draw_extra_info_t * draw_extra_info = (draw_extra_info_t*)buf->GetDrawExtraInfo();

bool ignore_clip = false;
if ( m_pbuffer->frmlinecount == 1 && m_pbuffer->frmlines[0]->word_count > 0 ) {
Expand Down Expand Up @@ -4815,6 +4816,26 @@ void LFormattedText::Draw( LVDrawBuf * buf, int x, int y, ldomMarkedRangeList *
frmline = m_pbuffer->frmlines[i];
if ( line_y + frmline->height > clip.top || ignore_clip )
{
// This line box is or has some part in the page regular clip.
// If it is fully inside the regular clip, we extend the clip
// to the provided content_overflow_clip to allow any glyph
// extending outside the line box (which can happen with a small
// interline space) to be drawn fully in the top or bottom margins.
// (We can't allow this for lines only partially in the clip, at
// least because of the case of isEmbeddedBlockBoxingInlineBox()
// below (big single line box possible spanning multiple pages)
// whose inner content lines will have to go thru the above
// regular clip check if we want to avoid the same inner line
// to appear on both prev and next pages.)
bool restore_orig_clip = false;
lvRect origClip;
if ( line_y >= clip.top && line_y + frmline->height <= clip.bottom ) {
if ( draw_extra_info ) {
restore_orig_clip = true;
buf->GetClipRect( &origClip );
buf->SetClipRect( &draw_extra_info->content_overflow_clip );
}
}
// process background

//lUInt32 bgcl = buf->GetBackgroundColor();
Expand Down Expand Up @@ -4966,7 +4987,6 @@ void LFormattedText::Draw( LVDrawBuf * buf, int x, int y, ldomMarkedRangeList *
// box, and restore it when done.
lvRect curclip;
buf->GetClipRect( &curclip ); // backup clip
draw_extra_info_t * draw_extra_info = (draw_extra_info_t*)buf->GetDrawExtraInfo();
if ( draw_extra_info ) {
buf->SetClipRect( &draw_extra_info->content_overflow_clip );
}
Expand Down Expand Up @@ -5093,6 +5113,9 @@ void LFormattedText::Draw( LVDrawBuf * buf, int x, int y, ldomMarkedRangeList *
}
}
#endif
if ( restore_orig_clip ) {
buf->SetClipRect(&origClip);
}
}
line_y += frmline->height;
}
Expand Down

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