Editor position work

2 files changed, 167 insertions, 48 deletions

diff --git a/src/ui_elements/TextEditor.c b/src/ui_elements/TextEditor.c
index fa85443..620abea 100644
--- a/src/ui_elements/TextEditor.c
+++ b/src/ui_elements/TextEditor.c
@@ -7,14 +7,23 @@
 #include <stdlib.h>
 #include <string.h>
 
-void HighlightCharacter(Vector2 lineStartPos, char *line, int index, Font *font, int height, int spacing) {
+float GetCursorXPos(TextArea *ta) {
+    int index = ta->CursorPosition.x;
+    char *line = ta->CurrentNode->text;
     float x_position = 0;
     for (int i = 0; i < index; i++) {
-        x_position += MeasureChar(font, height, line[i]);
-        x_position += spacing;
+        x_position += MeasureChar(ta->DisplayParams->font, 
+                ta->DisplayParams->font_size,
+                line[i]);
+        x_position += ta->DisplayParams->spacing;
     }
+    return x_position;
+}
+
+/// We pass x_position not to call GetCursorXPos twice (it's expencive)
+void DrawCursor(TextArea *ta, Vector2 lineStartPos, float x_position) {
     DrawLine(lineStartPos.x + x_position, lineStartPos.y, 
-            lineStartPos.x + x_position, lineStartPos.y + height, COLORSCHEME_BROWN);
+            lineStartPos.x + x_position, lineStartPos.y + ta->DisplayParams->font_size, COLORSCHEME_BROWN);
 }
 
 TextNode *CreateNode(TextNode *prev, TextNode *next) {
@@ -77,7 +86,7 @@ void AppendTextToNode(TextNode *base, char *new_text) {
     base->len += new_len;
 }
 
-TextArea *CreateTextArea() {
+TextArea *CreateTextArea(TextAreaDisplayParams *DisplayParams) {
     TextArea *outp = malloc(sizeof(TextArea));
     if (outp == NULL) return NULL;
 
@@ -90,9 +99,31 @@ TextArea *CreateTextArea() {
     outp->StartNode = start_node;
     outp->CurrentNode = start_node;
     outp->NodeLenth = 1;
+    outp->DisplayParams = DisplayParams;
     return outp;
 }
 
+void EnsureCursorIsInFrame(TextArea *ta) {
+    TextAreaDisplayParams *params = ta->DisplayParams;
+    Vector2 cursorPos = {
+        .x = GetCursorXPos(ta),
+        .y = ta->CursorPosition.y * ta->DisplayParams->font_size,
+    };
+
+    if (cursorPos.y < params->scroll_v) {
+        params->scroll_v = cursorPos.y;
+    } else if (params->scroll_v + params->_area_height - params->font_size < cursorPos.y) {
+        params->scroll_v = cursorPos.y + params->_area_height;
+    }
+
+    if (cursorPos.x < params->scroll_h) {
+        params->scroll_h = cursorPos.x - (params->_area_width / 2.0f);
+        if (params->scroll_h < 0) params->scroll_h = 0;
+    } else if (params->scroll_h + params->_area_width - params->font_size < cursorPos.x) {
+        params->scroll_h = cursorPos.x - (params->_area_width / 2.0f); 
+    }
+}
+
 bool PushNode(TextArea *ta) {
     if (ta == NULL || ta->CurrentNode == NULL) return false;
     TextNode *new_node = CreateNode(ta->CurrentNode, ta->CurrentNode->NextNode);
@@ -134,6 +165,7 @@ void PopCurrent(TextArea *ta) {
 
 void FreeTextArea(TextArea *ta) {
     FreeNodeRec(ta->StartNode);
+    if (ta->DisplayParams != NULL) free(ta->DisplayParams);
     free(ta);
 }
 
@@ -143,6 +175,26 @@ char GetCurrentChar(TextArea *ta) {
     return ta->CurrentNode->text[(int)ta->CursorPosition.x];
 }
 
+void MoveCursorDown(TextArea *ta) {
+    if (ta == NULL || ta->CurrentNode == NULL) return;
+    if (ta->CurrentNode->NextNode == NULL) return;
+    ta->CurrentNode = ta->CurrentNode->NextNode;
+
+    ta->CursorPosition.y += 1;
+    size_t line_len = ta->CurrentNode->len;
+    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
+}
+
+void MoveCursorUp(TextArea *ta) {
+    if (ta == NULL || ta->CurrentNode == NULL) return;
+    if (ta->CursorPosition.y == 0 || ta->CurrentNode->PrevNode == NULL) return;
+    ta->CurrentNode = ta->CurrentNode->PrevNode;
+    ta->CursorPosition.y -= 1;
+
+    size_t line_len = ta->CurrentNode->len;
+    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
+}
+
 /// This function is used in the skips through words (<C-arrows>)
 bool IsSkippable(char c) {
     return isalpha(c) || isdigit(c);
@@ -153,7 +205,14 @@ void MoveCursorRight(TextArea *ta) {
     ta->CursorPosition.x += 1;
 
     size_t line_len = ta->CurrentNode->len;
-    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
+    if (ta->CursorPosition.x > line_len) {
+        if (ta->CurrentNode->NextNode == NULL) {
+            ta->CursorPosition.x = line_len; 
+            return;
+        }
+        MoveCursorDown(ta);
+        ta->CursorPosition.x = 0;
+    }
 }
 
 void MoveCursorRightWord(TextArea *ta) {
@@ -163,7 +222,14 @@ void MoveCursorRightWord(TextArea *ta) {
     } while (IsSkippable(GetCurrentChar(ta)));
 
     size_t line_len = ta->CurrentNode->len;
-    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
+    if (ta->CursorPosition.x > line_len) {
+        if (ta->CurrentNode->NextNode == NULL) {
+            ta->CursorPosition.x = line_len; 
+            return;
+        }
+        MoveCursorDown(ta);
+        ta->CursorPosition.x = 0;
+    }
 }
 
 void MoveCursorEnd(TextArea *ta) {
@@ -174,7 +240,15 @@ void MoveCursorEnd(TextArea *ta) {
 void MoveCursorLeft(TextArea *ta) {
     if (ta == NULL || ta->CurrentNode == NULL) return;
     ta->CursorPosition.x -= 1;
-    if (ta->CursorPosition.x < 0) ta->CursorPosition.x = 0;
+
+    if (ta->CursorPosition.x < 0) {
+        if (ta->CursorPosition.y == 0 || ta->CurrentNode->PrevNode == NULL) {
+            ta->CursorPosition.x = 0;
+            return;
+        }
+        MoveCursorUp(ta);
+        MoveCursorEnd(ta);
+    }
 }
 
 void MoveCursorLeftWord(TextArea *ta) {
@@ -183,8 +257,14 @@ void MoveCursorLeftWord(TextArea *ta) {
         ta->CursorPosition.x -= 1;
     } while (IsSkippable(GetCurrentChar(ta)) && ta->CursorPosition.x > 0);
 
-    size_t line_len = ta->CurrentNode->len;
-    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
+    if (ta->CursorPosition.x < 0) {
+        if (ta->CursorPosition.y == 0 || ta->CurrentNode->PrevNode == NULL) {
+            ta->CursorPosition.x = 0;
+            return;
+        }
+        MoveCursorUp(ta);
+        MoveCursorEnd(ta);
+    }
 }
 
 void MoveCursorHome(TextArea *ta) {
@@ -192,26 +272,6 @@ void MoveCursorHome(TextArea *ta) {
     ta->CursorPosition.x = 0;
 }
 
-void MoveCursorDown(TextArea *ta) {
-    if (ta == NULL || ta->CurrentNode == NULL) return;
-    if (ta->CurrentNode->NextNode == NULL) return;
-    ta->CurrentNode = ta->CurrentNode->NextNode;
-
-    ta->CursorPosition.y += 1;
-    size_t line_len = ta->CurrentNode->len;
-    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
-}
-
-void MoveCursorUp(TextArea *ta) {
-    if (ta == NULL || ta->CurrentNode == NULL) return;
-    if (ta->CursorPosition.y == 0 || ta->CurrentNode->PrevNode == NULL) return;
-    ta->CurrentNode = ta->CurrentNode->PrevNode;
-    ta->CursorPosition.y -= 1;
-
-    size_t line_len = ta->CurrentNode->len;
-    if (ta->CursorPosition.x > line_len) ta->CursorPosition.x = line_len;
-}
-
 void BreakLine(TextArea *ta) {
     if (ta == NULL || ta->CurrentNode == NULL) return;
     if (ta->CursorPosition.x == 0) {
@@ -245,10 +305,12 @@ void BreakLine(TextArea *ta) {
     ta->CursorPosition.y += 1;
     ta->CursorPosition.x = 0;
     ta->CurrentNode = ta->CurrentNode->NextNode;
+    EnsureCursorIsInFrame(ta);
 }
 
 void InsertChar(TextArea *ta, char new_char) {
     if (ta == NULL || ta->CurrentNode == NULL) return;
+    EnsureCursorIsInFrame(ta);
     size_t line_len = ta->CurrentNode->len;
 
     if (line_len + 2 > ta->CurrentNode->cap) {
@@ -300,6 +362,7 @@ void DeleteChar(TextArea *ta) {
     ta->CursorPosition.x -= 1;
     ta->CurrentNode->len -= 1;
     if (ta->CurrentNode->len < 0) ta->CurrentNode->len = 0;
+    EnsureCursorIsInFrame(ta);
 }
 
 bool IsKeyPressedFix(int key) {
@@ -322,6 +385,16 @@ void HandleControlComands(TextArea *ta) {
     if (IsKeyPressedFix(KEY_RIGHT)) MoveCursorRightWord(ta);
     if (IsKeyPressedFix(KEY_LEFT)) MoveCursorLeftWord(ta);
 
+    if (IsKeyPressedFix(KEY_EQUAL)) {
+        if (ta->DisplayParams->font_size < MAX_FONT_SIZE)
+            ta->DisplayParams->font_size += 1;
+    }
+
+    if (IsKeyPressedFix(KEY_MINUS)) {
+        if (ta->DisplayParams->font_size > MIN_FONT_SIZE)
+            ta->DisplayParams->font_size -= 1;
+    }
+
     // emacs-like stuff
     if (IsKeyPressedFix(KEY_F)) MoveCursorRight(ta);
     if (IsKeyPressedFix(KEY_B)) MoveCursorLeft(ta);
@@ -380,27 +453,57 @@ void HandleKeyboard(TextArea *ta) {
     if (IsKeyPressedFix(KEY_F3)) PrintAllLines(ta); 
 }
 
+/// Assumes that the cursor is in the scroll area
+void HandleScroll(TextArea *ta, Rectangle rec) {
+    int scroll = GetMouseWheelMove() * SCROLL_SENC;
+    if (IsKeyDown(KEY_LEFT_SHIFT) || IsKeyDown(KEY_RIGHT_SHIFT)) {
+        ta->DisplayParams->scroll_h -= scroll;
+        if (ta->DisplayParams->scroll_h < 0) 
+            ta->DisplayParams->scroll_h = 0;
+        // TODO: figure out if we can easily get max width. Probably need some 
+        // lazy eval caching
+    } else {
+        int text_height = ta->NodeLenth * ta->DisplayParams->font_size;
+        int max_scroll = text_height - rec.height;
+        ta->DisplayParams->scroll_v -= scroll;
+        if (ta->DisplayParams->scroll_v < 0)
+            ta->DisplayParams->scroll_v = 0;
+        if (text_height > rec.height && ta->DisplayParams->scroll_v > max_scroll)
+            ta->DisplayParams->scroll_v = max_scroll;
+    }
+}
+
 /// draws a text area on the screen. Main draw entry point
-void DrawTextArea(TextArea *ta, Rectangle rec, Font *font, int height, int spacing, int *scroll) {
-    int vertical_acc = rec.y - *scroll;
-    int text_height = ta->NodeLenth * height;
-    int max_scroll = text_height - rec.height;
+void DrawTextArea(TextArea *ta, Rectangle rec) {
+    // those are used to move a cursor in frame when typing
+    ta->DisplayParams->_area_height = rec.height;
+    ta->DisplayParams->_area_width = rec.width;
 
-    if (text_height >= rec.height && IsMouseInRec(rec)) {
-        *scroll -= GetMouseWheelMove() * SCROLL_SENC;
-        if (*scroll < 0) *scroll = 0;
-        if (*scroll > max_scroll) *scroll = max_scroll;
+    TextAreaDisplayParams *params = ta->DisplayParams;
+    // int vertical_acc = rec.y - *scroll;
+ 
+    if (IsMouseInRec(rec)) {
+        HandleScroll(ta, rec);
     }
 
-    Vector2 pos = { .x = rec.x + spacing, .y = rec.y - *scroll };
+    Vector2 pos = { 
+        .x = rec.x + params->spacing - params->scroll_h,
+        .y = rec.y + params->spacing - params->scroll_v 
+    };
+
+    Vector2 cursorPos = {
+        .x = GetCursorXPos(ta),
+        .y = ta->CursorPosition.y * ta->DisplayParams->font_size,
+    };
+
     TextNode *node = ta->StartNode;
     BeginScissorMode(rec.x, rec.y, rec.width, rec.height);
     while (node != NULL) {
-        DrawTextEx(*font, node->text, pos, height, spacing, COLORSCHEME_BROWN);
+        DrawTextEx(*params->font, node->text, pos, params->font_size, params->spacing, COLORSCHEME_BROWN);
         if (node == ta->CurrentNode)
-            HighlightCharacter(pos, node->text, ta->CursorPosition.x, font, height, spacing);
+            DrawCursor(ta, pos, cursorPos.x);
         node = node->NextNode;
-        pos.y += height;
+        pos.y += params->font_size;
     }
     EndScissorMode();
 }
diff --git a/src/ui_elements/UI.h b/src/ui_elements/UI.h
index eaf17e8..9f126c3 100644
--- a/src/ui_elements/UI.h
+++ b/src/ui_elements/UI.h
@@ -7,6 +7,9 @@
 static const float SCROLL_SENC = 10;
 static const float TAB_WIDTH = 4;
 
+static const int MIN_FONT_SIZE = 10;
+static const int MAX_FONT_SIZE = 100;
+
 void DrawRecBordered(Rectangle rec, Color bg, Color border_color, int border_width);
 void DrawTextInRec(Rectangle rec, char *text, Font *font, int height, Color color, float padding, int *scroll);
 float MeasureChar(Font *font, int height, char symbol);
@@ -24,6 +27,21 @@ typedef struct {
     size_t cap;
 } TextNode;
 
+
+typedef struct {
+    Font *font;
+    int font_size;
+    int spacing;
+
+    int scroll_h;
+    int scroll_v;
+
+    /// DO NOT MODIFY THAT! It's for internal use only
+    int _area_width;
+    /// DO NOT MODIFY THAT! It's for internal use only
+    int _area_height;
+} TextAreaDisplayParams;
+
 typedef struct {
     TextNode *StartNode;
     /// For the quick access
@@ -31,17 +49,15 @@ typedef struct {
     size_t NodeLenth;
 
     Vector2 CursorPosition;
+    TextAreaDisplayParams *DisplayParams;
 } TextArea;
 
-TextArea *CreateTextArea();
-void FreeTextArea(TextArea *ta);
-void DrawTextArea(TextArea *ta, Rectangle rec, Font *font, int height, int spacing, int *scroll);
+TextArea *CreateTextArea(TextAreaDisplayParams *DisplayParams);
+void DrawTextArea(TextArea *ta, Rectangle rec);
 void InsertChar(TextArea *ta, char new_char);
 void DeleteChar(TextArea *ta);
 
 void HandleKeyboard(TextArea *ta);
-void MoveCursorRight(TextArea *ta);
-void MoveCursorLeft(TextArea *ta);
-void MoveCursorDown(TextArea *ta);
+void FreeTextArea(TextArea *ta);
 
 #endif // UI_ELEMENTS_H