Better UI Scaling

docs/CHANGELOG.md

@@ -53,6 +53,7 @@
     * `Proper Entity Shading` (Enabled By Default)
     * `Fix Sugar Position In Hand` (Enabled By Default)
     * `Fix Reloading Textures On Resize` (Enabled By Default)
+    * `Improved UI Scaling` (Enabled By Default)
   * Existing Functionality (All Enabled By Default)
     * `Fix Screen Rendering When Hiding HUD`
     * `Sanitize Usernames`

launcher/src/client/ui.cpp

@@ -1,5 +1,6 @@
 #include <vector>
 #include <limits>
+#include <cmath>
 
 #include <libreborn/util.h>
 
@@ -138,14 +139,16 @@ void ConfigurationUI::draw_main() const {
         state.render_distance = render_distances[render_distance_index];
     }
     // UI Scale
-    std::string scale_format = "%i";
-    scale_format += 'x';
+    const int precision = std::floor(state.gui_scale) == state.gui_scale ? 0 : 1;
+    std::string scale_format = "%." + std::to_string(precision) + "fx";
     if (state.gui_scale <= AUTO_GUI_SCALE) {
         scale_format = "Auto";
     }
-    int gui_scale_int = int(state.gui_scale);
-    if (ImGui::SliderInt(labels[2], &gui_scale_int, 0, 8, scale_format.c_str())) {
-        state.gui_scale = float(gui_scale_int);
+    char display_gui_scale[64];
+    sprintf(display_gui_scale, scale_format.c_str(), state.gui_scale);
+    float new_gui_scale = state.gui_scale;
+    if (ImGui::SliderFloat(labels[2], &new_gui_scale, 0, 8, display_gui_scale, ImGuiSliderFlags_NoRoundToFormat)) {
+        state.gui_scale = step_value(new_gui_scale);
         if (state.gui_scale < AUTO_GUI_SCALE) {
             state.gui_scale = AUTO_GUI_SCALE;
         }

libreborn/include/libreborn/util.h

@@ -65,3 +65,6 @@ std::string format_time(const char *fmt, int time);
 // Default MCPI Port
 // This Macro DOES NOT Control MCPI
 #define DEFAULT_MULTIPLAYER_PORT 19132
+
+// Step Value
+float step_value(float value, float step = 0.5f);

libreborn/src/util/flags/available-feature-flags

@@ -44,6 +44,7 @@ CATEGORY User Interface
     TRUE Improved Button Hover Behavior
     TRUE Classic Item Count UI
     TRUE Click Buttons On Mouse Down
+    TRUE Improved UI Scaling
 CATEGORY Rendering
     CATEGORY Optimizations
         TRUE Optimized Chunk Sorting

libreborn/src/util/util.cpp

@@ -3,6 +3,7 @@
 #include <sys/stat.h>
 #include <cstring>
 #include <ctime>
+#include <cmath>
 
 #include <libreborn/util.h>
 #include <libreborn/config.h>
@@ -135,3 +136,8 @@ std::string format_time(const char *fmt, const int time) {
     // This Will Break In 2038
     return _format_time(fmt, time);
 }
+
+// Step
+float step_value(const float value, const float step) {
+    return std::round(value / step) * step;
+}

mods/src/misc/ui.cpp

@@ -1,8 +1,11 @@
 #include <libreborn/patch.h>
 #include <libreborn/env.h>
+#include <libreborn/util.h>
 
 #include <symbols/minecraft.h>
 
+#include <media-layer/core.h>
+
 #include <GLES/gl.h>
 #include <SDL/SDL.h>
 
@@ -245,6 +248,29 @@ static void LocalPlayer_openTextEdit_injection(__attribute__((unused)) LocalPlay
     }
 }
 
+// Better GUI Scaling
+static void set_gui_scale(const float new_scale) {
+    union {
+        float a;
+        void *b;
+    } pun = {};
+    pun.a = new_scale;
+    patch_address((void *) 0x17520, pun.b);
+}
+static float calculate_scale(const float value, const float default_value) {
+    constexpr float initial_scale = 2.5f;
+    const float scale = initial_scale * (value / default_value);
+    return step_value(scale);
+}
+static void Minecraft_setSize_injection(Minecraft_setSize_t original, Minecraft *self, const int width, const int height) {
+    // Calculate Scale
+    const float a = calculate_scale(float(width), DEFAULT_WIDTH);
+    const float b = calculate_scale(float(height), DEFAULT_HEIGHT);
+    set_gui_scale(std::min(a, b));
+    // Call Original Method
+    original(self, width, height);
+}
+
 // Init
 void _init_misc_ui() {
     // Food Overlay
@@ -303,18 +329,24 @@ void _init_misc_ui() {
     }
 
     // Custom GUI Scale
+    bool patch_gui_scaling = false;
     const char *gui_scale_str = getenv(MCPI_GUI_SCALE_ENV);
     if (gui_scale_str != nullptr) {
         float gui_scale;
         env_value_to_obj(gui_scale, gui_scale_str);
         if (gui_scale > 0) {
+            patch_gui_scaling = true;
+            set_gui_scale(gui_scale);
+        }
+    }
+    if (feature_has("Improved UI Scaling", server_disabled) && !patch_gui_scaling) {
+        overwrite_calls(Minecraft_setSize, Minecraft_setSize_injection);
+        patch_gui_scaling = true;
+    }
+    if (patch_gui_scaling) {
         unsigned char nop_patch[4] = {0x00, 0xf0, 0x20, 0xe3}; // "nop"
         patch((void *) 0x173e8, nop_patch);
         patch((void *) 0x173f0, nop_patch);
-            uint32_t gui_scale_raw;
-            memcpy(&gui_scale_raw, &gui_scale, sizeof (gui_scale_raw));
-            patch_address((void *) 0x17520, (void *) gui_scale_raw);
-        }
     }
 
     // Don't Wrap Text On '\r' Or '\t' Because They Are Actual Characters In MCPI

symbols/src/game/Minecraft.def

@@ -17,6 +17,7 @@ method LevelStorageSource *getLevelSource() = 0x16e84;
 method void handleMouseDown(int param_1, bool can_destroy) = 0x1584c;
 method void handleBuildAction(uint *build_action_intention) = 0x15920;
 method void joinMultiplayer(const PingedCompatibleServer &server) = 0x165f4;
+method void setSize(int width, int height) = 0x173a4;
 
 virtual-method void update() = 0x24;
 virtual-method int handleBack(bool do_nothing) = 0x34;