From: Sebastian Harl <sh@tokkee.org>
Date: Fri, 21 Oct 2011 13:02:25 +0000 (+0200)
Subject: gtk-tpdfv: Center PDF page vertically and horizontally.
X-Git-Url: https://git.tokkee.org/?p=tpdfview.git;a=commitdiff_plain;h=3e7481766429955636c4969d8f306c2b4305f3cd

gtk-tpdfv: Center PDF page vertically and horizontally.
---

diff --git a/src/gtk-tpdfv.c b/src/gtk-tpdfv.c
index 4398719..771dff9 100644
--- a/src/gtk-tpdfv.c
+++ b/src/gtk-tpdfv.c
@@ -179,6 +179,14 @@ gtk_tpdfv_expose(GtkWidget *tpdfv, GdkEventExpose *event)
 	gtk_tpdfv_t *pdf;
 	cairo_t *cr;
 
+	gdouble width, height;
+
+	gdouble page_width  = 0.0;
+	gdouble page_height = 0.0;
+
+	double zoom_factor  = 1.0;
+	double x, y;
+
 	pdf = GTK_TPDFV_GET_PRIVATE(tpdfv);
 
 	if (! pdf)
@@ -189,23 +197,15 @@ gtk_tpdfv_expose(GtkWidget *tpdfv, GdkEventExpose *event)
 			event->area.width, event->area.height);
 	cairo_clip(cr);
 
-	/* zoom, scrolling */
+	poppler_page_get_size(pdf->current_page, &page_width, &page_height);
+	width  = (gdouble)tpdfv->allocation.width;
+	height = (gdouble)tpdfv->allocation.height;
+
+	/* zoom */
 	if (pdf->zoom_mode == TPDFV_ZOOM_CUSTOM) {
-		cairo_scale(cr, pdf->zoom_factor, pdf->zoom_factor);
+		zoom_factor = pdf->zoom_factor;
 	}
 	else {
-		gdouble width;
-		gdouble height;
-
-		gdouble page_width  = 0.0;
-		gdouble page_height = 0.0;
-
-		double zoom_factor  = 1.0;
-
-		poppler_page_get_size(pdf->current_page, &page_width, &page_height);
-		width  = (gdouble)tpdfv->allocation.width;
-		height = (gdouble)tpdfv->allocation.height;
-
 		if (pdf->zoom_mode == TPDFV_ZOOM_WIDTH) {
 			zoom_factor = (double)(width / page_width);
 		}
@@ -219,11 +219,14 @@ gtk_tpdfv_expose(GtkWidget *tpdfv, GdkEventExpose *event)
 		else {
 			assert(0);
 		}
-
-		cairo_scale(cr, zoom_factor, zoom_factor);
 	}
+	cairo_scale(cr, zoom_factor, zoom_factor);
+
+	/* centered position / scrolling */
+	x = (double)(width - page_width * zoom_factor) / 2.0 / zoom_factor;
+	y = (double)(height - page_height * zoom_factor) / 2.0 / zoom_factor;
 
-	cairo_translate(cr, pdf->delta_x, pdf->delta_y);
+	cairo_translate(cr, x + pdf->delta_x, y + pdf->delta_y);
 
 	poppler_page_render(pdf->current_page, cr);