eda-tools/eeshow/gui.c

/*
 * gui.c - GUI for eeshow
 *
 * Written 2016 by Werner Almesberger
 * Copyright 2016 by Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/*
 * Resources:
 *
 * http://zetcode.com/gfx/cairo/cairobackends/
 * https://developer.gnome.org/gtk3/stable/gtk-migrating-2-to-3.html
 */

#include <stdio.h>

#include <gtk/gtk.h>

#include "cro.h"
#include "gfx.h"
#include "sch.h"
#include "gui.h"


struct gui_ctx {
	GtkWidget *da;
	const struct sch_ctx *sch;

	struct cro_ctx *gfx_ctx;
	int w, h;
	int xmin, ymin;

	unsigned zoom;		/* scale by 1.0 / (1 << zoom) */
	int x, y;		/* center, in eeschema coordinates */

	bool panning;
	int pan_x, pan_y;
} gui_ctx;


/* ----- Rendering --------------------------------------------------------- */


static gboolean on_draw_event(GtkWidget *widget, cairo_t *cr,
    gpointer user_data)
{
	const struct gui_ctx *ctx = user_data;
	GtkAllocation alloc;

	float f = 1.0 / (1 << ctx->zoom);
	int x, y;

	gtk_widget_get_allocation(ctx->da, &alloc);
//	x = -(ctx->xo - ctx->w / 2) * f - (ctx->x - alloc.width / 2);
//	y = -(ctx->yo - ctx->h / 2) * f - (ctx->y - alloc.height / 2);
	x = -(ctx->xmin + ctx->x) * f + alloc.width / 2;
	y = -(ctx->ymin + ctx->y) * f + alloc.height / 2;
	cro_canvas_draw(ctx->gfx_ctx, cr, x, y, f);

	return FALSE;
}


static void render(struct gui_ctx *ctx)
{
	char *argv[] = { "gui", NULL };

	gfx_init(&cro_canvas_ops, 1, argv);
	sch_render(ctx->sch->sheets);
	cro_canvas_end(gfx_ctx, &ctx->w, &ctx->h, &ctx->xmin, &ctx->ymin);
	ctx->gfx_ctx = gfx_ctx;

	ctx->x = ctx->w >> 1;
	ctx->y = ctx->h >> 1;
	// gfx_end();
}


/* ----- Tools ------------------------------------------------------------- */


static void canvas_coord(const struct gui_ctx *ctx,
    int ex, int ey, int *x, int *y)
{
	int sx, sy;
	GtkAllocation alloc;

	gtk_widget_get_allocation(ctx->da, &alloc);
	sx = ex - alloc.width / 2;
	sy = ey - alloc.height / 2;
	*x = (sx << ctx->zoom) + ctx->x;
	*y = (sy << ctx->zoom) + ctx->y;
}


/* ----- Panning ----------------------------------------------------------- */


static void pan_begin(struct gui_ctx *ctx, int x, int y)
{
	if (ctx->panning)
		return;
	ctx->panning = 1;
	ctx->pan_x = x;
	ctx->pan_y = y;
}


static void pan_update(struct gui_ctx *ctx, int x, int y)
{
	if (!ctx->panning)
		return;
	
	ctx->x -= (x - ctx->pan_x) << ctx->zoom;
	ctx->y -= (y - ctx->pan_y) << ctx->zoom;
	ctx->pan_x = x;
	ctx->pan_y = y;

	gtk_widget_queue_draw(ctx->da);
}


static void pan_end(struct gui_ctx *ctx, int x, int y)
{
	pan_update(ctx, x, y);
	ctx->panning = 0;
}


/* ----- Zoom -------------------------------------------------------------- */



static void zoom_in(struct gui_ctx *ctx, int x, int y)
{
	if (ctx->zoom == 0)
		return;
	ctx->zoom--;
	ctx->x = (ctx->x + x) / 2;
	ctx->y = (ctx->y + y) / 2;
	gtk_widget_queue_draw(ctx->da);
}


static void zoom_out(struct gui_ctx *ctx, int x, int y)
{
	if (ctx->w >> ctx->zoom <= 16)
		return;
	ctx->zoom++;
	ctx->x = 2 * ctx->x - x;
	ctx->y = 2 * ctx->y - y;
	gtk_widget_queue_draw(ctx->da);
}


/* ----- Event handlers ---------------------------------------------------- */


static gboolean motion_notify_event(GtkWidget *widget, GdkEventMotion *event,
    gpointer data)
{
	struct gui_ctx *ctx = data;
	int x, y;

	canvas_coord(ctx, event->x, event->y, &x, &y);
//	fprintf(stderr, "motion\n");
	pan_update(ctx, event->x, event->y);
	return TRUE;
}


static gboolean button_press_event(GtkWidget *widget, GdkEventButton *event,
    gpointer data)
{
	struct gui_ctx *ctx = data;
	int x, y;

	canvas_coord(ctx, event->x, event->y, &x, &y);
	fprintf(stderr, "button press\n");
	switch (event->button) {
	case 1:
		break;
	case 2:
		pan_begin(ctx, event->x, event->y);
		break;
	case 3:
		break;
	}
	return TRUE;
}


static gboolean button_release_event(GtkWidget *widget, GdkEventButton *event,
    gpointer data)
{
	struct gui_ctx *ctx = data;
	int x, y;

	canvas_coord(ctx, event->x, event->y, &x, &y);
	fprintf(stderr, "button release\n");
	switch (event->button) {
	case 1:
		break;
	case 2:
		pan_end(ctx, event->x, event->y);
		break;
	case 3:
		break;
	}
	return TRUE;
}


static gboolean key_press_event(GtkWidget *widget, GdkEventKey *event,
    gpointer data)
{
fprintf(stderr, "key %d\n", event->keyval);
	switch (event->keyval) {
	case GDK_KEY_q:
		gtk_main_quit();
	}
	return TRUE;
}


static gboolean scroll_event(GtkWidget *widget, GdkEventScroll *event,
    gpointer data)
{
	struct gui_ctx *ctx = data;
	int x, y;

	canvas_coord(ctx, event->x, event->y, &x, &y);
	switch (event->direction) {
	case GDK_SCROLL_UP:
		zoom_in(ctx, x, y);
		break;
	case GDK_SCROLL_DOWN:
		zoom_out(ctx, x, y);
		break;
	default:
		/* ignore */;
	}
	return TRUE;
}


/* ----- Initialization ---------------------------------------------------- */


int gui(struct sch_ctx *sch)
{
	GtkWidget *window;
	struct gui_ctx ctx = {
		.sch		= sch,
		.zoom		= 4,	/* scale by 1 / 16 */
		.panning	= 0,
	};

	render(&ctx);

	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);

	ctx.da = gtk_drawing_area_new();
	gtk_container_add(GTK_CONTAINER(window), ctx.da);

	g_signal_connect(G_OBJECT(ctx.da), "draw",
	    G_CALLBACK(on_draw_event), &ctx);
	g_signal_connect(G_OBJECT(ctx.da), "motion_notify_event",
	    G_CALLBACK(motion_notify_event), &ctx);
	g_signal_connect(G_OBJECT(ctx.da), "button_press_event",
	    G_CALLBACK(button_press_event), &ctx);
	g_signal_connect(G_OBJECT(ctx.da), "button_release_event",
	    G_CALLBACK(button_release_event), &ctx);
	g_signal_connect(G_OBJECT(ctx.da), "scroll_event",
	    G_CALLBACK(scroll_event), &ctx);
	g_signal_connect(G_OBJECT(ctx.da), "key_press_event",
	    G_CALLBACK(key_press_event), &ctx);
	g_signal_connect(window, "destroy",
	    G_CALLBACK(gtk_main_quit), NULL);

	gtk_widget_set_can_focus(ctx.da, TRUE);

	gtk_widget_set_events(ctx.da,
	    GDK_EXPOSE | GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK |
	    GDK_KEY_PRESS_MASK |
	    GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
	    GDK_SCROLL_MASK |
	    GDK_POINTER_MOTION_MASK);

//	gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
//	gtk_window_set_default_size(GTK_WINDOW(window), 400, 90);
	gtk_window_set_title(GTK_WINDOW(window), "eeshow");

	gtk_widget_show_all(window);

	gtk_main();

	return 0;
}