WindowServer+LibGfx: Move CursorParams to LibGfx

They will be used by MouseSettings in the next commit.

3 files changed, 138 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGfx/CMakeLists.txt b/Userland/Libraries/LibGfx/CMakeLists.txt
index b16f1caf50..92625cace3 100644
--- a/Userland/Libraries/LibGfx/CMakeLists.txt
+++ b/Userland/Libraries/LibGfx/CMakeLists.txt
@@ -8,6 +8,7 @@ set(SOURCES
     ClassicStylePainter.cpp
     ClassicWindowTheme.cpp
     Color.cpp
+    CursorParams.cpp
     DDSLoader.cpp
     DisjointRectSet.cpp
     Emoji.cpp
diff --git a/Userland/Libraries/LibGfx/CursorParams.cpp b/Userland/Libraries/LibGfx/CursorParams.cpp
new file mode 100644
index 0000000000..31ae7105ae
--- /dev/null
+++ b/Userland/Libraries/LibGfx/CursorParams.cpp
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Format.h>
+#include <AK/LexicalPath.h>
+#include <LibGfx/Bitmap.h>
+#include <LibGfx/CursorParams.h>
+
+namespace Gfx {
+
+CursorParams CursorParams::parse_from_filename(StringView const& cursor_path, Gfx::IntPoint const& default_hotspot)
+{
+    LexicalPath path(cursor_path);
+    auto file_title = path.title();
+    auto last_dot_in_title = file_title.find_last('.');
+    if (!last_dot_in_title.has_value() || last_dot_in_title.value() == 0) {
+        // No encoded params in filename. Not an error, we'll just use defaults
+        return { default_hotspot };
+    }
+    auto params_str = file_title.substring_view(last_dot_in_title.value() + 1);
+
+    CursorParams params(default_hotspot);
+    bool in_display_scale_part = false;
+    for (size_t i = 0; i + 1 < params_str.length() && !in_display_scale_part;) {
+        auto property = params_str[i++];
+
+        auto value = [&]() -> Optional<size_t> {
+            size_t k = i;
+            while (k < params_str.length()) {
+                auto ch = params_str[k];
+                if (ch < '0' || ch > '9')
+                    break;
+                k++;
+            }
+            if (k == i)
+                return {};
+            auto parsed_number = params_str.substring_view(i, k - i).to_uint();
+            if (!parsed_number.has_value())
+                return {};
+            i = k;
+            return parsed_number.value();
+        }();
+        if (!value.has_value()) {
+            dbgln("Failed to parse value for property '{}' from parsed cursor path: {}", property, cursor_path);
+            return { default_hotspot };
+        }
+        switch (property) {
+        case 'x':
+            params.m_hotspot.set_x(value.value());
+            params.m_have_hotspot = true;
+            break;
+        case 'y':
+            params.m_hotspot.set_y(value.value());
+            params.m_have_hotspot = true;
+            break;
+        case 'f':
+            if (value.value() > 1)
+                params.m_frames = value.value();
+            break;
+        case 't':
+            if (value.value() >= 100 && value.value() <= 1000)
+                params.m_frame_ms = value.value();
+            else
+                dbgln("Cursor frame rate outside of valid range (100-1000ms)");
+            break;
+        case '-':
+            in_display_scale_part = true;
+            break;
+        default:
+            dbgln("Ignore unknown property '{}' with value {} parsed from cursor path: {}", property, value.value(), cursor_path);
+            return { default_hotspot };
+        }
+    }
+
+    return params;
+}
+
+CursorParams CursorParams::constrained(Gfx::Bitmap const& bitmap) const
+{
+    CursorParams params(*this);
+    auto rect = bitmap.rect();
+    if (params.m_frames > 1) {
+        if (rect.width() % params.m_frames == 0) {
+            rect.set_width(rect.width() / (int)params.m_frames);
+        } else {
+            dbgln("Cannot divide cursor dimensions {} into {} frames", rect, params.m_frames);
+            params.m_frames = 1;
+        }
+    }
+    if (params.m_have_hotspot)
+        params.m_hotspot.constrain(rect);
+    else
+        params.m_hotspot = rect.center();
+    return params;
+}
+
+}
diff --git a/Userland/Libraries/LibGfx/CursorParams.h b/Userland/Libraries/LibGfx/CursorParams.h
new file mode 100644
index 0000000000..d3bbd07945
--- /dev/null
+++ b/Userland/Libraries/LibGfx/CursorParams.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/StringView.h>
+#include <LibGfx/Point.h>
+
+namespace Gfx {
+
+class CursorParams {
+public:
+    static CursorParams parse_from_filename(StringView const&, Gfx::IntPoint const&);
+
+    CursorParams() = default;
+
+    CursorParams(Gfx::IntPoint const& hotspot)
+        : m_hotspot(hotspot)
+    {
+    }
+    CursorParams constrained(Gfx::Bitmap const&) const;
+
+    Gfx::IntPoint const& hotspot() const { return m_hotspot; }
+    unsigned frames() const { return m_frames; }
+    unsigned frame_ms() const { return m_frame_ms; }
+
+private:
+    Gfx::IntPoint m_hotspot;
+    unsigned m_frames { 1 };
+    unsigned m_frame_ms { 0 };
+    bool m_have_hotspot { false };
+};
+
+}