sch2fig/text.c (guess_width): move width guessing to the graphics back-ends

sch2fig/cairo.c

@@ -53,6 +53,12 @@ static inline int cx(int x)
 }
 
 
+static inline int xc(int x)
+{
+	return x * 5;
+}
+
+
 static inline int cy(int y)
 {
 	return y / 5;
@@ -142,6 +148,9 @@ void cr_arc(void *ctx, int x, int y, int r, int sa, int ea,
 }
 
 
+#define	TEXT_STRETCH	1.3
+
+
 void cr_text(void *ctx, int x, int y, const char *s, unsigned size,
     enum text_align align, int rot, unsigned color, unsigned layer)
 {
@@ -149,7 +158,7 @@ void cr_text(void *ctx, int x, int y, const char *s, unsigned size,
 	cairo_text_extents_t ext;
 	cairo_matrix_t m;
 
-	cairo_set_font_size(cc->cr, cx(size) * 1.3);
+	cairo_set_font_size(cc->cr, cx(size) * TEXT_STRETCH);
 	cairo_text_extents(cc->cr, s, &ext);
 
 	set_color(cc->cr, color);
@@ -177,6 +186,17 @@ void cr_text(void *ctx, int x, int y, const char *s, unsigned size,
 }
 
 
+unsigned cr_text_width(void *ctx, const char *s, unsigned size)
+{
+	struct cairo_ctx *cc = ctx;
+	cairo_text_extents_t ext;
+
+	cairo_set_font_size(cc->cr, cx(size) * TEXT_STRETCH);
+	cairo_text_extents(cc->cr, s, &ext);
+	return xc(ext.width);
+}
+
+
 /* ----- Initializatio and termination ------------------------------------- */
 
 
@@ -213,10 +233,11 @@ void cr_end(void *ctx)
 
 const struct gfx_ops cairo_ops = {
 	// .line	= cr_line,	@@@ later
-	.poly	= cr_poly,
-	.circ	= cr_circ,
-	.arc	= cr_arc,
-	.text	= cr_text,
-	.init	= cr_init,
-	.end	= cr_end,
+	.poly		= cr_poly,
+	.circ		= cr_circ,
+	.arc		= cr_arc,
+	.text		= cr_text,
+	.text_width	= cr_text_width,
+	.init		= cr_init,
+	.end		= cr_end,
 };

sch2fig/fig.c

@@ -14,6 +14,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <math.h>
 #include <assert.h>
 
@@ -161,6 +162,16 @@ void fig_text(void *ctx, int x, int y, const char *s, unsigned size,
 }
 
 
+unsigned fig_text_width(void *ctx, const char *s, unsigned size)
+{
+	/*
+	 * Note that we stretch the text size, so the ratio is larger than
+	 * expressed here.
+	 */
+	return strlen(s) * size * 1.0;
+}
+
+
 /* ----- FIG file header --------------------------------------------------- */
 
 
@@ -232,11 +243,12 @@ void *fig_init(const char *template, int n_vars, const char **vars)
 
 
 const struct gfx_ops fig_ops = {
-	.line	= fig_line,
-	.rect	= fig_rect,
-	.poly	= fig_poly,
-	.circ	= fig_circ,
-	.arc	= fig_arc,
-	.text	= fig_text,
-	.init	= fig_init,
+	.line		= fig_line,
+	.rect		= fig_rect,
+	.poly		= fig_poly,
+	.circ		= fig_circ,
+	.arc		= fig_arc,
+	.text		= fig_text,
+	.text_width	= fig_text_width,
+	.init		= fig_init,
 };

sch2fig/gfx.c

@@ -77,6 +77,12 @@ void gfx_text(int x, int y, const char *s, unsigned size,
 }
 
 
+unsigned gfx_text_width(const char *s, unsigned size)
+{
+	return gfx_ops->text_width(gfx_ctx, s, size);
+}
+
+
 void gfx_init(const struct gfx_ops *ops,
     const char *template, int n_vars, const char **vars)
 {

sch2fig/gfx.h

@@ -30,6 +30,7 @@ struct gfx_ops {
 	    int color, int fill_color, unsigned layer);
 	void (*text)(void *ctx, int x, int y, const char *s, unsigned size,
 	    enum text_align align, int rot, unsigned color, unsigned layer);
+	unsigned (*text_width)(void *ctx, const char *s, unsigned size);
 	void *(*init)(const char *template, int n_vars, const char **vars);
 	void (*end)(void *ctx);
 };
@@ -47,6 +48,7 @@ void gfx_arc(int x, int y, int r, int sa, int ea,
     int color, int fill_color, unsigned layer);
 void gfx_text(int x, int y, const char *s, unsigned size,
     enum text_align align, int rot, unsigned color, unsigned layer);
+unsigned gfx_text_width(const char *s, unsigned size);
 
 /* inititalization and termination */
 

sch2fig/text.c

@@ -115,22 +115,14 @@ void text_fig(const struct text *txt, int color, unsigned layer)
 }
 
 
-static unsigned guess_width(const struct text *txt)
-{
-	/*
-	 * Note that fig.c stretches the text size, so the ratio is larger than
-	 * expressed here.
-	 */
-	return strlen(txt->s) * txt->size * 1.0;
-}
-
-
 void text_rel(const struct text *txt, enum text_align xr, enum text_align yr,
     int dx, int dy, int *res_x, int *res_y)
 {
-	dx -= align(guess_width(txt), txt->hor);
+	int width = gfx_text_width(txt->s, txt->size);
+
+	dx -= align(width, txt->hor);
 	dy += align(txt->size, txt->vert);
-	dx += align(guess_width(txt), xr);
+	dx += align(width, xr);
 	dy -= align(txt->size, yr);
 	if (res_x)
 		*res_x = txt->x + rx(dx, dy, txt->rot);