DenysMedvid/pdf2htmlEX
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Code

merge states with different (but proportional) matrices

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This commit is contained in:
Lu Wang 2013-04-05 22:17:40 +08:00
parent ab2588a5fd
commit 952cd4d3c9
1 changed files with 19 additions and 22 deletions
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41
src/HTMLRenderer/state.cc
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@ -141,6 +141,12 @@ void HTMLRenderer::check_state_change(GfxState * state)
bool need_rescale_font = false;
bool draw_text_scale_changed = false;
// save current info for later use
HTMLState old_html_state = cur_html_state;
double old_tm[6];
memcpy(old_tm, cur_text_tm, sizeof(old_tm));
double old_draw_text_scale = draw_text_scale;
// text position
// we've been tracking the text position positively in the update*** functions
if(all_changed || text_pos_changed)
@ -148,9 +154,6 @@ void HTMLRenderer::check_state_change(GfxState * state)
need_recheck_position = true;
}
// save current info for later use
auto old_font_info = cur_html_state.font_info;
double old_font_size = cur_html_state.font_size;
// font name & size
if(all_changed || font_changed)
{
@ -180,10 +183,6 @@ void HTMLRenderer::check_state_change(GfxState * state)
}
}
// backup the current ctm for need_recheck_position
double old_tm[6];
memcpy(old_tm, cur_text_tm, sizeof(old_tm));
// ctm & text ctm & hori scale & rise
if(all_changed || ctm_changed || text_mat_changed || hori_scale_changed || rise_changed)
{
@ -276,25 +275,23 @@ void HTMLRenderer::check_state_change(GfxState * state)
/*
* CurTM * (cur_tx, cur_ty, 1)^T = OldTM * (draw_tx + dx, draw_ty + dy, 1)^T
*
* the first 4 elements of CurTM and OldTM should be the same
* the first 4 elements of CurTM and OldTM should be the proportional
* otherwise the following text cannot be parallel
*
* CurTM[4] - OldTM[4] = OldTM[0] * (draw_tx + dx - cur_tx) + OldTM[2] * (draw_ty + dy - cur_ty)
* CurTM[5] - OldTM[5] = OldTM[1] * (draw_tx + dx - cur_tx) + OldTM[3] * (draw_ty + dy - cur_ty)
*
* TODO, try to merge when cur_tm and old_tm are proportional
* NOTE:
* dx,dy are handled by the old state. so they should be multiplied by old_draw_text_scale
*/
bool merged = false;
double dx = 0;
double dy = 0;
if(tm_equal(old_tm, cur_text_tm, 4))
if(tm_equal(old_html_state.transform_matrix, cur_html_state.transform_matrix, 4))
{
double det = old_tm[0] * old_tm[3] - old_tm[1] * old_tm[2];
if(!equal(det, 0))
{
double lhs1 = cur_text_tm[4] - old_tm[4] - old_tm[0] * (draw_tx - cur_tx) - old_tm[2] * (draw_ty - cur_ty);
double lhs2 = cur_text_tm[5] - old_tm[5] - old_tm[1] * (draw_tx - cur_tx) - old_tm[3] * (draw_ty - cur_ty);
double lhs1 = cur_text_tm[0] * cur_tx + cur_text_tm[2] * cur_ty + cur_text_tm[4] - old_tm[0] * draw_tx - old_tm[2] * draw_ty - old_tm[4];
double lhs2 = cur_text_tm[1] * cur_tx + cur_text_tm[3] * cur_ty + cur_text_tm[5] - old_tm[1] * draw_tx - old_tm[3] * draw_ty - old_tm[5];
/*
* Now the equation system becomes
*
@ -319,12 +316,12 @@ void HTMLRenderer::check_state_change(GfxState * state)
// otherwise we merge the lines only when
// - text are not shifted to the left too much
// - text are not moved too high or too low
if((dx * draw_text_scale) >= -(old_font_info->ascent - old_font_info->descent) * old_font_size - EPS)
if((dx * old_draw_text_scale) >= -(old_html_state.font_info->ascent - old_html_state.font_info->descent) * old_html_state.font_size - EPS)
{
double oldymin = old_font_info->descent * old_font_size;
double oldymax = old_font_info->ascent * old_font_size;
double ymin = dy * draw_text_scale + cur_html_state.font_info->descent * cur_html_state.font_size;
double ymax = dy * draw_text_scale + cur_html_state.font_info->ascent * cur_html_state.font_size;
double oldymin = old_html_state.font_info->descent * old_html_state.font_size;
double oldymax = old_html_state.font_info->ascent * old_html_state.font_size;
double ymin = dy * old_draw_text_scale + cur_html_state.font_info->descent * cur_html_state.font_size;
double ymax = dy * old_draw_text_scale + cur_html_state.font_info->ascent * cur_html_state.font_size;
if((ymin <= oldymax + EPS) && (ymax >= oldymin - EPS))
{
merged = true;
@ -338,14 +335,14 @@ void HTMLRenderer::check_state_change(GfxState * state)
if(merged)
{
text_line_buf->append_offset(dx * draw_text_scale);
text_line_buf->append_offset(dx * old_draw_text_scale);
if(equal(dy, 0))
{
cur_html_state.vertical_align = 0;
}
else
{
cur_html_state.vertical_align = (dy * draw_text_scale);
cur_html_state.vertical_align = (dy * old_draw_text_scale);
new_line_state = max<NewLineState>(new_line_state, NLS_SPAN);
}
draw_tx = cur_tx;