diff options
Diffstat (limited to 'apps/pdfapp.c')
| -rw-r--r-- | apps/pdfapp.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/apps/pdfapp.c b/apps/pdfapp.c index f199f12e..c42ba856 100644 --- a/apps/pdfapp.c +++ b/apps/pdfapp.c @@ -6,6 +6,7 @@ #include <ctype.h> /* for tolower() */ #define ZOOMSTEP 1.142857 +#define BEYOND_THRESHHOLD 40 enum panning { @@ -987,6 +988,7 @@ void pdfapp_onmouse(pdfapp_t *app, int x, int y, int btn, int modifiers, int sta app->ispanning = 1; app->selx = x; app->sely = y; + app->beyondy = 0; } if (btn == 3 && !app->ispanning) { @@ -1048,7 +1050,55 @@ void pdfapp_onmouse(pdfapp_t *app, int x, int y, int btn, int modifiers, int sta { int newx = app->panx + x - app->selx; int newy = app->pany + y - app->sely; + /* Scrolling beyond limits implies flipping pages */ + /* Are we requested to scroll beyond limits? */ + if (newy + app->image->h < app->winh || newy > 0) + { + /* Yes. We can assume that deltay != 0 */ + int deltay = y - app->sely; + /* Check whether the panning has occured in the + * direction that we are already crossing the + * limit it. If not, we can conclude that we + * have switched ends of the page and will thus + * start over counting. + */ + if( app->beyondy == 0 || (app->beyondy ^ deltay) >= 0 ) + { + /* Updating how far we are beyond and + * flipping pages if beyond threshhold + */ + app->beyondy += deltay; + if (app->beyondy > BEYOND_THRESHHOLD) + { + if( app->pageno > 1 ) + { + app->pageno--; + pdfapp_showpage(app, 1, 1, 1); + newy = -app->image->h; + } + app->beyondy = 0; + } + else if (app->beyondy < -BEYOND_THRESHHOLD) + { + if( app->pageno < app->pagecount ) + { + app->pageno++; + pdfapp_showpage(app, 1, 1, 1); + newy = 0; + } + app->beyondy = 0; + } + } + else + app->beyondy = 0; + } + /* Although at this point we've already determined that + * or that no scrolling will be performed in + * y-direction, the x-direction has not yet been taken + * care off. Therefore + */ pdfapp_panview(app, newx, newy); + app->selx = x; app->sely = y; } |