1 files changed, 185 insertions, 0 deletions
diff --git a/src/ui/widget/page-size-preview.cpp b/src/ui/widget/page-size-preview.cpp
new file mode 100644
index 0000000..40e2ea5
--- /dev/null
+++ b/src/ui/widget/page-size-preview.cpp
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * @file
+ *
+ * Page size preview widget
+ */
+/*
+ * Authors:
+ *   Mike Kowalski
+ *
+ * Copyright (C) 2021 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "page-size-preview.h"
+#include "display/cairo-utils.h"
+#include "2geom/rect.h"
+
+namespace Inkscape {    
+namespace UI {
+namespace Widget {
+
+PageSizePreview::PageSizePreview() {
+    show();
+}
+
+void rounded_rectangle(const Cairo::RefPtr<Cairo::Context>& cr, double x, double y, double w, double h, double r) {
+    cr->begin_new_sub_path();
+    cr->arc(x + r, y + r, r, M_PI, 3 * M_PI / 2);
+    cr->arc(x + w - r, y + r, r, 3 * M_PI / 2, 2 * M_PI);
+    cr->arc(x + w - r, y + h - r, r, 0, M_PI / 2);
+    cr->arc(x + r, y + h - r, r, M_PI / 2, M_PI);
+    cr->close_path();
+}
+
+void set_source_rgba(const Cairo::RefPtr<Cairo::Context>& ctx, unsigned int rgba) {
+    ctx->set_source_rgba(SP_RGBA32_R_F(rgba), SP_RGBA32_G_F(rgba), SP_RGBA32_B_F(rgba), SP_RGBA32_A_F(rgba));
+}
+
+bool PageSizePreview::on_draw(const Cairo::RefPtr<Cairo::Context>& ctx) {
+    auto alloc = get_allocation();
+    double width = alloc.get_width();
+    double height = alloc.get_height();
+    // too small to fit anything?
+    if (width <= 2 || height <= 2) return false;
+
+    double x = 0;//alloc.get_x();
+    double y = 0;//alloc.get_y();
+
+    if (_draw_checkerboard) {
+        // auto device_scale = get_scale_factor();
+        Cairo::RefPtr<Cairo::Pattern> pattern(new Cairo::Pattern(ink_cairo_pattern_create_checkerboard(_desk_color)));
+        ctx->save();
+        ctx->set_operator(Cairo::OPERATOR_SOURCE);
+        ctx->set_source(pattern);
+        rounded_rectangle(ctx, x, y, width, height, 2.0);
+        ctx->fill();
+        ctx->restore();
+    }
+    else {
+        rounded_rectangle(ctx, x, y, width, height, 2.0);
+        set_source_rgba(ctx, _desk_color);
+        ctx->fill();
+    }
+
+    // use lesser dimension to prevent page from changing size when
+    // switching from portrait to landscape or vice versa
+    auto size = std::round(std::min(width, height) * 0.90); // 90% to leave margins
+    double w, h;
+    if (_width > _height) {
+        w = size;
+        h = std::round(size * _height / _width);
+    }
+    else {
+        h = size;
+        w = std::round(size * _width / _height);
+    }
+    if (w < 2) w = 2;
+    if (h < 2) h = 2;
+
+    // center page
+    double ox = std::round(x + (width - w) / 2);
+    double oy = std::round(y + (height - h) / 2);
+    Geom::Rect rect(ox, oy, ox + w, oy + h);
+
+    ctx->rectangle(rect.left(), rect.top(), rect.width(), rect.height());
+
+    if (_draw_checkerboard) {
+        Cairo::RefPtr<Cairo::Pattern> pattern(new Cairo::Pattern(ink_cairo_pattern_create_checkerboard(_page_color)));
+        ctx->save();
+        ctx->set_operator(Cairo::OPERATOR_SOURCE);
+        ctx->set_source(pattern);
+        ctx->rectangle(rect.left(), rect.top(), rect.width(), rect.height());
+        ctx->fill();
+        ctx->restore();
+    }
+    else {
+        ctx->rectangle(rect.left(), rect.top(), rect.width(), rect.height());
+        set_source_rgba(ctx, _page_color | 0xff);
+        ctx->fill();
+    }
+
+    // draw cross
+    {
+        double gradient_size = 4;
+        double cx = std::round(x + (width - gradient_size) / 2);
+        double cy = std::round(y + (height - gradient_size) / 2);
+        auto horz = Cairo::LinearGradient::create(x, cy, x, cy + gradient_size);
+        auto vert = Cairo::LinearGradient::create(cx, y, cx + gradient_size, y);
+
+        horz->add_color_stop_rgba(0.0, 0, 0, 0, 0.0);
+        horz->add_color_stop_rgba(0.5, 0, 0, 0, 0.2);
+        horz->add_color_stop_rgba(0.5, 1, 1, 1, 0.8);
+        horz->add_color_stop_rgba(1.0, 1, 1, 1, 0.0);
+
+        vert->add_color_stop_rgba(0.0, 0, 0, 0, 0.0);
+        vert->add_color_stop_rgba(0.5, 0, 0, 0, 0.2);
+        vert->add_color_stop_rgba(0.5, 1, 1, 1, 0.8);
+        vert->add_color_stop_rgba(1.0, 1, 1, 1, 0.0);
+
+        ctx->rectangle(x, cy, width, gradient_size);
+        ctx->set_source(horz);
+        ctx->fill();
+
+        ctx->rectangle(cx, y, gradient_size, height);
+        ctx->set_source(vert);
+        ctx->fill();
+    }
+
+    ctx->rectangle(rect.left(), rect.top(), rect.width(), rect.height());
+    set_source_rgba(ctx, _page_color);
+    ctx->fill();
+
+    if (_draw_border) {
+        // stoke; not pixel aligned, just like page on canvas
+        ctx->rectangle(rect.left(), rect.top(), rect.width(), rect.height());
+        set_source_rgba(ctx, _border_color);
+        ctx->set_line_width(1);
+        ctx->stroke();
+
+        if (_draw_shadow) {
+            const auto a = (exp(-3 * SP_RGBA32_A_F(_border_color)) - 1) / (exp(-3) - 1);
+            ink_cairo_draw_drop_shadow(ctx, rect, 12, _border_color, a);
+        }
+    }
+
+    return true;
+}
+
+void PageSizePreview::draw_border(bool border) {
+    _draw_border = border;
+    queue_draw();
+}
+
+void PageSizePreview::set_desk_color(unsigned int rgba) {
+    _desk_color = rgba | 0xff; // desk always opaque
+    queue_draw();
+}
+void PageSizePreview::set_page_color(unsigned int rgba) {
+    _page_color = rgba;
+    queue_draw();
+}
+void PageSizePreview::set_border_color(unsigned int rgba) {
+    _border_color = rgba;
+    queue_draw();
+}
+
+void PageSizePreview::enable_drop_shadow(bool shadow) {
+    _draw_shadow = shadow;
+    queue_draw();
+}
+
+void PageSizePreview::enable_checkerboard(bool checkerboard) {
+    _draw_checkerboard = checkerboard;
+    queue_draw();
+}
+
+void PageSizePreview::set_page_size(double width, double height) {
+    _width = width;
+    _height = height;
+    queue_draw();
+}
+
+} } } // namespace Inkscape/Widget/UI