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pstext: clip lines by text box #9035

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Merged
joa-quim merged 1 commit into from
May 25, 2026
+80 −21
Merged

pstext: clip lines by text box #9035

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58 changes: 58 additions & 0 deletions src/postscriptlight.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4045,6 +4045,64 @@ int PSL_plotsegment (struct PSL_CTRL *PSL, double x0, double y0, double x1, doub
return (PSL_NO_ERROR);
}

int PSL_plotline_clipped_by_textbox(struct PSL_CTRL *PSL, double x0, double y0, double x1, double y1,
double fontsize, char *text, double angle, int justify, double offset[2]) {
/* Draw a line from (x0,y0) to the text-reference point (x1,y1), clipping out the part
* that falls inside the text bounding box (plus optional clearance offset) around (x1,y1).
* The box is sized for the given text/fontsize/justify and rotated by angle. Used for
* leader lines from a data point to an offset text label (pstext -D...+v<pen>).
*/
const char *jx[3] = {"0", "PSL_dim_w 2 div neg", "PSL_dim_w neg"};
const char *jy[3] = {"0", "PSL_dim_h 2 div neg", "PSL_dim_h neg"};
int x_just = 0, y_just = 0, ixl, iyl;
double a_rad, ca, sa, dx_u, dy_u, xl_u, yl_u, saved_fontsize;

if (text == NULL || text[0] == '\0') /* No text -- just draw the line */
return (PSL_plotsegment(PSL, x0, y0, x1, y1));

if (justify > 1) {
x_just = (justify + 3) % 4; /* 0=left, 1=center, 2=right */
y_just = justify / 4; /* 0=bottom, 1=middle, 2=top */
}

/* Compute line-start position in the local (rotated) coord system whose origin is at (x1,y1) */
a_rad = angle * D2R;
ca = cos(a_rad); sa = sin(a_rad);
dx_u = x0 - x1; dy_u = y0 - y1;
xl_u = dx_u * ca + dy_u * sa;
yl_u = -dx_u * sa + dy_u * ca;
ixl = (int)lrint(xl_u * PSL->internal.x2ix);
iyl = (int)lrint(yl_u * PSL->internal.y2iy);

saved_fontsize = PSL->current.fontsize; /* PSL_deftextdim will update the cache; restore after grestore */

PSL_comment(PSL, "PSL_plotline_clipped_by_textbox begin\n");
PSL_command(PSL, "V "); /* gsave */
PSL_command(PSL, "%d %d T ", psl_ix(PSL, x1), psl_iy(PSL, y1));
if (angle != 0.0) PSL_command(PSL, "%.12g R ", angle);
PSL_deftextdim(PSL, "PSL_dim", fontsize, text); /* Defines PSL_dim_w, _h, _d, _x0, _x1 in PS */
PSL_defunits(PSL, "PSL_dx", offset[0]);
PSL_defunits(PSL, "PSL_dy", offset[1]);

/* Build even-odd clip path: huge outer rectangle + textbox rectangle (the hole) */
PSL_command(PSL, "N -10000000 -10000000 M 20000000 0 D 0 20000000 D -20000000 0 D P\n");
PSL_command(PSL, "%s PSL_dim_x0 add PSL_dx sub %s PSL_dim_d add PSL_dy sub M ",
jx[x_just], jy[y_just]);
PSL_command(PSL, "PSL_dim_x1 PSL_dim_x0 sub PSL_dx 2 mul add 0 D ");
PSL_command(PSL, "0 PSL_dim_h PSL_dim_d sub PSL_dy 2 mul add D ");
PSL_command(PSL, "PSL_dim_x1 PSL_dim_x0 sub PSL_dx 2 mul add neg 0 D P\n");
PSL_command(PSL, "eoclip N\n");

/* Draw the (now clipped) line from (xl, yl) to (0, 0) in local coords */
PSL_command(PSL, "N %d %d M %d %d D S\n", ixl, iyl, -ixl, -iyl);

PSL_command(PSL, "U\n"); /* grestore -- pops clip and CTM */
PSL_comment(PSL, "PSL_plotline_clipped_by_textbox end\n");

PSL->current.fontsize = saved_fontsize;
return (PSL_NO_ERROR);
}

int PSL_setcurrentpoint (struct PSL_CTRL *PSL, double x, double y) {
/* Set the current point only */
PSL->internal.ix = psl_ix (PSL, x);
Expand Down
1 change: 1 addition & 0 deletions src/postscriptlight.h
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Expand Up @@ -480,6 +480,7 @@ EXTERN_MSC int PSL_plotpolygon (struct PSL_CTRL *PSL, double *x, double *y, int
EXTERN_MSC int PSL_plotgradienttriangle (struct PSL_CTRL *PSL, double *x, double *y, double *rgb, int steps);
EXTERN_MSC int PSL_plotgradienttriangle_gouraud (struct PSL_CTRL *PSL, double *x, double *y, double *rgb);
EXTERN_MSC int PSL_plotsegment (struct PSL_CTRL *PSL, double x0, double y0, double x1, double y1);
EXTERN_MSC int PSL_plotline_clipped_by_textbox (struct PSL_CTRL *PSL, double x0, double y0, double x1, double y1, double fontsize, char *text, double angle, int justify, double offset[2]);
EXTERN_MSC int PSL_plotsymbol (struct PSL_CTRL *PSL, double x, double y, double param[], int symbol);
EXTERN_MSC int PSL_plottext (struct PSL_CTRL *PSL, double x, double y, double fontsize, char *text, double angle, int justify, int mode);
EXTERN_MSC int PSL_plottextbox (struct PSL_CTRL *PSL, double x, double y, double fontsize, char *text, double angle, int justify, double offset[], int mode);
Expand Down
42 changes: 21 additions & 21 deletions src/pstext.c
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Expand Up @@ -998,19 +998,19 @@ EXTERN_MSC int GMT_pstext (void *V_API, int mode, void *args) {

PSL_setfont (PSL, T.font.id);
gmt_plane_perspective (GMT, GMT->current.proj.z_project.view_plane, 0.0);
if (T.boxflag & 32) { /* Draw line from original point to shifted location */
gmt_setpen (GMT, &T.vecpen);
PSL_plotsegment (PSL, xx[0], yy[0], xx[1], yy[1]);
if (T.space_flag) { /* Meant % of fontsize */
offset[0] = 0.01 * T.x_space * T.font.size / PSL_POINTS_PER_INCH;
offset[1] = 0.01 * T.y_space * T.font.size / PSL_POINTS_PER_INCH;
}
else {
offset[0] = T.x_space;
offset[1] = T.y_space;
}
if (T.boxflag & 32) { /* Draw line from original point to shifted location, clipped at textbox edge */
gmt_setpen(GMT, &T.vecpen);
PSL_plotline_clipped_by_textbox(PSL, xx[0], yy[0], xx[1], yy[1], T.font.size, use_text, T.paragraph_angle, T.block_justify, offset);
}
if (!Ctrl->G.mode && T.boxflag & 3) { /* Plot the box beneath the text */
if (T.space_flag) { /* Meant % of fontsize */
offset[0] = 0.01 * T.x_space * T.font.size / PSL_POINTS_PER_INCH;
offset[1] = 0.01 * T.y_space * T.font.size / PSL_POINTS_PER_INCH;
}
else {
offset[0] = T.x_space;
offset[1] = T.y_space;
}
if (Ctrl->S.active) { /* Lay down shaded box first */
PSL_setfill (PSL, Ctrl->S.fill.rgb, 0); /* shade color */
PSL_plottextbox (PSL, plot_x + Ctrl->S.off[GMT_X], plot_y + Ctrl->S.off[GMT_Y], T.font.size, use_text, T.paragraph_angle, T.block_justify, offset, T.boxflag & 4);
Expand Down Expand Up @@ -1477,19 +1477,19 @@ EXTERN_MSC int GMT_pstext (void *V_API, int mode, void *args) {
}
PSL_setfont (PSL, T.font.id);
gmt_plane_perspective (GMT, GMT->current.proj.z_project.view_plane, in[GMT_Z]);
if (T.boxflag & 32) { /* Draw line from original point to shifted location */
if (T.space_flag) { /* Meant % of fontsize */
offset[0] = 0.01 * T.x_space * T.font.size / PSL_POINTS_PER_INCH;
offset[1] = 0.01 * T.y_space * T.font.size / PSL_POINTS_PER_INCH;
}
else {
offset[0] = T.x_space;
offset[1] = T.y_space;
}
if (T.boxflag & 32) { /* Draw line from original point to shifted location, clipped at textbox edge */
gmt_setpen (GMT, &T.vecpen);
PSL_plotsegment (PSL, xx[0], yy[0], xx[1], yy[1]);
PSL_plotline_clipped_by_textbox(PSL, xx[0], yy[0], xx[1], yy[1], T.font.size, use_text, T.paragraph_angle, T.block_justify, offset);
}
if (!Ctrl->G.mode && T.boxflag & 3) { /* Plot the box beneath the text */
if (T.space_flag) { /* Meant % of fontsize */
offset[0] = 0.01 * T.x_space * T.font.size / PSL_POINTS_PER_INCH;
offset[1] = 0.01 * T.y_space * T.font.size / PSL_POINTS_PER_INCH;
}
else {
offset[0] = T.x_space;
offset[1] = T.y_space;
}
if (Ctrl->S.active) { /* Lay down shaded box first */
PSL_setfill (PSL, Ctrl->S.fill.rgb, 0); /* shade color */
PSL_plottextbox (PSL, plot_x + Ctrl->S.off[GMT_X], plot_y + Ctrl->S.off[GMT_Y], T.font.size, use_text, T.paragraph_angle, T.block_justify, offset, T.boxflag & 4);
Expand Down
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